Prince William and Kate Middleton

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge leave after attending the Easter Mattins Service at St. George's Chapel at Windsor Castle on April 1, 2018.

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge leave after attending the Easter Mattins Service at St. George's Chapel at Windsor Castle on April 1, 2018.

Catherine, Duchess of Cambridge takes part in a Commonwealth Quiz in which athletes, coaches and supporters are questioned on their knowledge of the Commonwealth, at a SportsAid event held at the Copperbox Arena in the Olympic Park in London on March 22, 2018.

Catherine, Duchess of Cambridge greets children on her arrival to undertake engagements celebrating the Commonwealth, at a SportsAid event held at the Copperbox Arena in the Olympic Park in London on March 22, 2018.

Catherine, Duchess of Cambridge takes part in preparations for a Commonwealth Big Lunch at St. Luke's Community Centre in London on March 22, 2018, as part of the Commonwealth Day celebrations.

Catherine, Duchess of Cambridge during a symposium she convened on early intervention for children and families with The Royal Foundation, at the Royal Society of Medicine in London on March 21, 2018.

Catherine, Duchess of Cambridge and Prince William visit Cavalry Barracks Hounslow in London, Britain on March 17, 2018.

Britain's Catherine, Duchess of Cambridge, leaves after attending the Easter Mattins Service at St. George's Chapel at Windsor Castle on April 1, 2018.

Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge, attend the St. Patrick's Day Parade with the 1st Battalion Irish Guards at Cavalry Barracks, Hounslow in London on March 17, 2018.

Catherine, Duchess of Cambridge waves from her car as she leaves after the Easter Mattins Service at St. George's Chapel at Windsor Castle on April 1, 2018 in Windsor, England.

Britain's Catherine, Duchess of Cambridge, attends the St. Patrick's Day Parade with the 1st Battalion Irish Guards at Cavalry Barracks, Hounslow in London on March 17, 2018.

Kate Middleton, Prince William and Meghan Markle

Kate, Prince William and Meghan Markle wait for the Queen to leave the traditional Christmas Day church service at St. Mary Magdalene Church in Sandringham, England, on Dec. 25, 2017.

Kate poses after the traditional Christmas Day church service at St. Mary Magdalene Church in Sandringham, England, on Dec. 25, 2017.

Kate Middleton

Kate leaves the Portobello Trust in London on Dec. 12, 2017.

Kate and Prince William

Kate and Prince William attend the Children's Global Media Summit at the Manchester Central Convention Complex on Dec. 6, 2017.

Kate Middleton

Kate covers her ears during a visit to the factory of Acme Whistles in Birmingham, England, on Nov. 22, 2017.

Prince William, Kate Middleton, Prince George and Princess Charlotte

Prince William, Kate Middleton, Prince George and Princess Charlotte pose at Kensington Palace, which was used as the family's Christmas photo.

Britain's Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge, arrive at Dammtor Station during a visit in Hamburg, Germany, on July 21, 2017.

Katherine, the Duchess of Cambridge, and Prince William, the Duke of Cambridge, attend the Queen's birthday party at the British ambassadorial residence in Berlin on July 19, 2017.

Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge, chat with Nils Juergens of Claerchen's as they arrive at a reception at Claerchen's Ballhaus dance hall following a day in Heidelberg on the second day of the royal visit to Germany on July 20, 2017.

Britain's Prince William, Duke of Cambridge and his wife Kate, Duchess of Cambridge, take a walk on the Old Bridge in the historic center of Heidelberg, southern Germany on July 20, 2017.

Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge, depart after a visit to the Maritime Museum to celebrate the joint UK-German year of science, which for 2017 is focused on oceans, during an official visit to Poland and Germany in Hamburg, Germany, on July 21, 2017.

Britain's Dutchess of Cambridge, Catherine, arrives to visit the Elbphilharmonie concert hall in Hamburg, northern Germany, on July 21, 2017.

Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge, make a toast at the queen's birthday garden party at the Orangery, Lazienki Park in Warsaw, on day 1 of their official visit to Poland on July 17, 2017.

Britain's Prince William, Duke of Cambridge, far right, and Catherine, Duchess of Cambridge, far left, during a meeting with German President Frank-Walter Steinmeier, right, and his wife Elke Buedenbender, left, at the Bellevue Palace in Berlin, Germany, July 19, 2017.

Andreas Goebes of the bakers guild Heidelberg, right, watches as Kate, the Duchess of Cambridge, and Britain's Prince William, the Duke of Cambridge, shape pretzels during their visit to the market in the historic center of the southern German town of Heidelberg on July 20, 2017.

Britain's Prince William and his wife Kate, the Duchess of Cambridge, talk with German President Frank-Walter Steinmeier and his wife, Elke Buedenbender, as they sit in the garden of the presidential residence at Bellevue Palace in Berlin on Wednesday, July 19, 2017.

Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge visit the Gdansk Shakespeare Theatre in Poland during an official visit to Poland on July 18, 2017.

The Duke and Duchess of Cambridge, William and Kate. take a tour of a traditional German market in the Central Square of Heidelberg, Germany, on day two of their official visit to the country on July 20, 2017.

Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge don white lab coats during their visit to the German Cancer Research Institute in Heidelberg, on day two of their official visit to Germany on July 20, 2017.

The Duke and Duchess of Cambridge, William and Kate, attend a Queen Elizabeth II birthday garden party at the residence of the British Ambassador in Berlin on July19 , 2017.

Children welcome Kate, the Duchess of Cambridge, in front of the presidential palace, in Warsaw, Poland, Monday, July 17, 2017.

Prince William, Duke of Cambridge, and Kate, Duchess of Cambridge, watch the Gentlemen's Singles final between Roger Federer of Switzerland and Marin Cilic of Croatia during the Wimbledon Lawn Tennis Championships at the All England Lawn Tennis and Croquet Club at Wimbledon on July 16, 2017, in London.

The Duke and Duchess of Cambridge, William and Kate, arrive with their children, Princess Charlotte and Prince George, on day one of their official visit to Warsaw, Poland, on July 17, 2017.

The Duke and Duchess of Cambridge, William and Kate, with their children arrive at Berlin Tegel Airport during an official visit to Germany on July 19, 2017.

Prince William, Duke of Cambridge, and Kate, Duchess of Cambridge visit the Gdansk Shakespeare Theatre in Gdansk, Poland, on July 18, 2017.

Katherine, the Duchess of Cambridge, and Prince William, the Duke of Cambridge, attend the Queen's birthday party at the British ambassadorial residence in Berlin on July 19, 2017.

The Duke and Duchess of Cambridge, William and Kate, arrive with their children at Berlin Tegel Airport on July 19, 2017.

Prince William, left, Kate and Prince Harry pose while wearing charity headbands issued by The Royal Foundation of the Duke and Duchess of Cambridge and Prince Harry. The three royals are spearheading a campaign to encourage people to talk openly about mental health issues.

Prince William and Kate arrive at a "Service of Hope" at Westminster Abbey, two weeks after the March 22 London terror attack, in London, on Wednesday, April 5, 2017.

Prince William, left, Kate and Prince Harry stand together after arriving for a "Service of Hope" at Westminster Abbey, two weeks after the March 22 London terror attack, in London, on Wednesday, April 5, 2017.

Kate, Duchess of Cambridge, is escorted by gallery director Nicholas Cullinan at the 2017 Portrait Gala, a fundraising event, at the National Portrait Gallery in London on March 28, 2017.

Prince William visits a "Les Voisins in Action" event highlighting the strong ties between the young people of France and the UK during an official two-day visit to Paris on March 18, 2017.

Catherine, Duchess of Cambridge, visits a "Les Voisins in Action" event highlighting the strong ties between the young people of France and the UK during an official two-day visit to Paris on March 18, 2017.

Prince William, Duke of Cambridge, and Cambridge Duchess Kate Middleton, attend the Six Nations tournament Rugby Union match between France and Wales at the Stade de France in Saint-Denis, outside Paris, on March 18, 2017.

Kate, Duchess of Cambridge, and Prince William listen to wounded French army members as they visit the Hotel des Invalides in Paris on Saturday, March 18, 2017.

Prince William and Kate, Duchess of Cambridge, meet with people near the Eiffel Tower in Paris on March 18, 2017.

Prince William and Kate pose for photographers in Trocadero Square in Paris, France, on March 18, 2017.

Prince William and Duchess Kate meet with France's President Francois Hollande in Paris on March 17, 2017.

Britain's Prince William, Duke of Cambridge, and his wife Kate, Duchess of Cambridge, arrive for a dinner at the British Embassy in Paris on March 17, 2017.

Prince William and Kate, Duchess of Cambridge, arrive for a dinner at the British Embassy in Paris on March 17, 2017.

Kate, Duchess of Cambridge, center, and the wife of Britain's ambassador to France Lord Ed Llewellyn, Anna, listen to Prince William during a reception at the British embassy in Paris on Friday, March 17, 2017.

French President Francois Hollande, center, welcomes Prince William and Kate at the Elysee Palace in Paris on Friday, March 17, 2017.

Prince William, Duke of Cambridge, helps children complete a construction task as he launches the new Prince William Award with SkillForce in Abergavenny, Wales, on March 1, 2017.

Prince William greets children as he launches the new Prince William Award with SkillForce in Abergavenny, Wales, on March 1, 2017.

Kate, Duchess of Cambridge, smiles while talking to a child during a visit to the Ronald McDonald House Evelina in London on Tuesday, Feb. 28, 2017.

Duchess Kate receives a bouquet of flowers as she arrives at Ronald McDonald House Evelina in London on Tuesday, Feb. 28, 2017.

Duchess Kate, Duchess of Cambridge, enters a reception to mark the launch of the UK-India Year of Culture 2017 at Buckingham Palace in London on Monday, Feb. 27, 2017.

Britain's Prince William, and Kate, Duchess of Cambridge, attend a reception to mark the launch of the UK-India Year of Culture 2017 at Buckingham Palace in London on Monday, Feb. 27, 2017.

Kate, Duchess of Cambridge, plays pool during her visit to Action for Children project MIST, a child and adolescent mental health project that works with children who are living in care, in Torfaen, Wales, on Wednesday, Feb. 22, 2017.

Prince George leaves Christmas Day service at St Mark's Church in Englefield, England, on Sunday, Dec. 25, 2016.

Catherine, Duchess of Cambridge, and Princess Charlotte watch a man inflate a balloon at a children's party at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Catherine, Duchess of Cambridge, and Prince George attend a party at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Prince George and Prince William attend a children's party for Military families at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Prince William, Duchess Kate, Princess Charlotte and Prince George attend a children's party for Military families at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Princess Charlotte attends a party at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Prince George plays with bubbles at a children's party for Military families at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Prince William, Kate, Charlotte and George, attend a party at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Prince George attends a children's party for Military families at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Princess Charlotte plays with a dog at a children's party for Military families at Government House in Victoria, British Columbia, Canada, on Sept. 29, 2016.

Kate, Duchess of Cambridge, holds an eagle feather given to her by a young girl as Prince William looks on during a welcoming ceremony in Carcross, Yukon, Canada, on Wednesday, Sept. 28, 2016.

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge, in Carcross, Yukon, Canada, on Sept. 28, 2016.

Prince William and Catherine, the Duchess of Cambridge, in Carcross, Yukon, Canada, on Sept. 28, 2016.

Prince William and Kate meet with Canadian Prime Minister Justin Trudeau and his wife Sophie at Immigrant Services Society of BC in Vancouver, Canada on Sept. 25, 2016.

Prince William and Kate walk the factory floor as they visit Hayward Tyler in Luton where they presented the company with The Queen's Award for Enterprise and opened their newly built Centre of Excellence on Aug. 24, 2016.

Duchess Catherine and Prince George visit the Royal International Air Tattoo at RAF Fairford in Fairford, England on July 8, 2016.

Prince William and Prince George during a visit to the Royal International Air Tattoo at RAF Fairford in Fairford, England on July 8, 2016.

Prince William, Kate and Prince George during a visit to the Royal International Air Tattoo at RAF Fairford in Fairford, England on July 8, 2016.

Britain's Princess Charlotte poses at Anmer Hall in Norfolk, England, in an undated photo released on Sunday, May 1, 2016.

Britain's Princess Charlotte poses at Anmer Hall in Norfolk, England, in an undated photo released on Sunday, May 1, 2016.

Britain's Princess Charlotte poses at Anmer Hall in Norfolk, England, in an undated photo released on Sunday, May 1, 2016.

Princess Charlotte poses at Anmer Hall in Norfolk, England, in an undated photo released on Sunday, May 1, 2016.

Britain's Prince William and Kate Duchess of Cambridge enjoy a snow ball fight as they enjoy a short private break skiing in the French Alps on Thursday, March 3, 2016.

Prince William and Princess Charlotte in the French Alps on Thursday, March 3, 2016.

Britain's Prince William and Duchess of Cambridge, with their children, Princess Charlotte and Prince George in the French Alps on Thursday, March 3, 2016.

Prince William Kate with their children, Princess Charlotte and Prince George, enjoying a skiing vacation in the French Alps on Thursday, March 3, 2016.

Prince George on his first day at the Westacre Montessori nursery school near Sandringham in Norfolk, eastern England, on Wednesday, Jan. 6, 2016.

Catherine, Duchess of Cambridge, Britain's Prince William, and their two children Prince George and Princess Charlotte at Kensington Palace in London in late October 2015.

Prince George on his first day at the Westacre Montessori nursery school near Sandringham in Norfolk, England on Jan. 6, 2016.

Princess Charlotte, at Anmer Hall in Sandringham, England.

Princess Charlotte with her cuddly toy dog, at Anmer Hall in Sandringham, England.

Catherine, The Duchess of Cambridge, holding daughter Princess Charlotte, and Prince William, The Duke of Cambridge, carrying son Prince George in Sandringham, Norfolk, Britain on July 5, 2015.

Princess Charlotte after her christening at St. Mary Magdalene Church in Sandringham, England on Sunday, July 5, 2015.

Prince William and Kate leave St. Mary's Hospital's Lindo Wing in London with their newborn daughter, Charlotte, on Saturday, May 2, 2015.

Princess Charlotte Elizabeth Diana, daughter of Prince William and Kate was born at Mary's Hospital in London, on Saturday, May 2, 2015.

Charlotte Elizabeth Diana, daughter of Britain's Prince William and Kate, Duchess of Cambridge, is all bundled up to leave St. Mary's Hospital in London on Saturday, May 2, 2015.

Prince William and Kate Middleton arrive at The Carlyle Hotel in Manhattan on Sunday, Dec. 7, 2014.

Prince William and Kate arrive at The Carlyle Hotel in Manhattan on Sunday, Dec. 7, 2014.

Britain's Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge attend the ceremonial welcome ceremony for Singapore's President Tony Tan Keng Yam at the start of a state visit at Horse Guards Parade in central London on Oct. 21, 2014

Prince William and wife Catherine, the Duke and Duchess of Cambridge, visit Pembroke Refinery in Pembroke, Wales, for its 50th anniversary on Saturday, Nov. 8, 2014.

Prince William and wife Catherine, the Duke and Duchess of Cambridge, look on during their meeting with Singapore President Tony Tan Keng Yam at the Royal Garden Hotel in London on Tuesday, Oct. 21, 2014.

Prince William and wife Catherine, the Duke and Duchess of Cambridge, walk through a sea of blood-red ceramic poppies inside the moat at the Tower of London in London on Tuesday, Aug. 5, 2014.

Prince William and wife Catherine, the Duke and Duchess of Cambridge, attend a World War I commemoration ceremony at Le Mémorial Interallié in Liege, Belgium, on Monday, Aug. 4, 2014.

Prince William and Kate arrive at the SSE Hydro arena to watch gymnastics during Day Five of the Commonwealth Games in Glasgow, Scotland, on Tuesday, July 28, 2014.

Prince Harry, Prince William and Kate watch Scotland play Wales at Glasgow National Hockey Centre during Day Five of the Commonwealth Games in Glasgow, Scotland, on Tuesday, July 28, 2014.

Prince William, Duchess Kate and Prince Harry watch the Tour De France in Harrogate, northern England, on Saturday, July 5, 2014.

Prince William and Kate, the Duke and Duchess of Cambridge, stand on the podium at the finish of Stage 1 of the Tour De France in Harrogate in northern England, on Saturday, July 5, 2014.

Duchess Kate and Prince William attend Day 9 of the Wimbledon Lawn Tennis Championships at the All England Lawn Tennis and Croquet Club at Wimbledon in London on July 2, 2014.

Prince William and Catherine, the Duke and Duchess of Cambridge, attend Day 9 of the Wimbledon Lawn Tennis Championships at the All England Lawn Tennis and Croquet Club at Wimbledon in London on July 2, 2014.

Prince William and Kate stand on the balcony of Buckingham Palace during the "Trooping the Color" parade in London on Saturday, June 14, 2014.

Prince William, Duke of Cambridge, and Catherine, Duchess of Cambridge, attend a remembrance ceremony in Arromanches, Normandy, on Friday, June 6, 2014.

Prince William and Duchess Kate attend a remembrance ceremony in Arromanches, Normandy, on Friday, June 6, 2014.

Prince William and Kate sample whisky during a tour of The Famous Grouse Distillery in Crieff, Scotland, on Friday, May 29, 2014.

Prince William and Duchess Kate watch the Bird Show at Taronga Zoo in Sydney, Australia on April 20, 2014.

Prince William and Catherine, Duchess of Cambridge, share a smile during the ANZAC Day march at the Australian War Memorial in Canberra on April 25, 2014.

Prince William, Kate Middleton and Prince George leave Fairbairne Airbase as they head back to the UK after finishing their Royal Visit to Australia on April 25, 2014.

Prince William and Kate attend a reception hosted by the Governor General Peter Cosgrove and Lady Cosgrove at Government House in Canberra, Australia on April 24, 2014.

Prince William and wife Kate laugh at a reception in Australia's Parliament House in Canberra, Australia on Thursday, April 24, 2014.

Catherine, duchess of Cambridge, and eight-month-old Prince George arrive at Wellington Military Terminal in Wellington, New Zealand on April 7, 2014.

Kate, carrying baby Prince George, and Prince William arrive at Wellington Military Terminal in Wellington, New Zealand on April 7, 2014.

Catherine, the duchess of Cambridge, chats with school children at the official welcome ceremony at Government House, in Wellington, New Zealand on April 7, 2014.

Prince William and Kate before meeting with Royal British Legion and London Poppy Day appeal staff and volunteers, at Kensington Palace in London on Nov. 7, 2013.

Prince William and Kate ride with television personality Barbara Windsor, second right, on a 1960s Routemaster bus on route to meeting London Poppy Day staff and volunteers on Nov. 7, 2013.

Prince William and Kate talk to Queen Elizabeth II as they arrive, holding their son Prince George, at Chapel Royal in St. James's Palace in London on Oct. 23, 2013.

Prince William, Duke of Cambridge arrives, holding his son Prince George, at Chapel Royal in St. James's Palace, before the baby's christening by the Archbishop of Canterbury in London on Oct. 23, 2013.

Prince William trains with players in the grounds of Buckingham Palace to mark the Football Association's 150th anniversary on Oct. 7, 2013.

Britain's Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge arrive at Breakwater country park to start the Ring O Fire Anglesey Coastal Ultra Marathon in Holyhead on Anglesey, north Wales on Aug. 30, 2013.

Prince William, Duchess Catherine with Prince George of Cambridge, at the Middleton family home in Bucklebury, Berkshire, in early August, 2013.

Prince William and Duchess Kate with their newborn baby boy, Prince George of Cambridge, in early August 2013.

Prince William and Kate leave St. Mary's Hospital's exclusive Lindo Wing in London holding their newborn son, Prince George on July 23, 2013.

Kate Middleton, Prince William, right, and Prince Harry raise their wands on the film set used to depict Diagon Alley in the "Harry Potter" films during the inauguration of "Warner Bros. Studios Leavesden" near Watford, England on April 26, 2013.

Prince Charles, Kate and Prince William stand together during a visit to Dumfries House near Cumnock, south of Glasgow, Scotland on April 5, 2013.

Kate Middleton meets members of the 1st Battalion Irish Guards during the St Patrick's Day parade at Mons Barracks in Aldershot, England on March 17, 2013.

Britain's Kate the Duchess of Cambridge receives flowers from a little girl at the 1st Battalion Irish Guards' St Patrick's Day Parade at Mons Barracks in Aldershot, England on March 17, 2013.

Prince William and his wife Kate smile to the public during a walk through a central city park in Kuala Lumpur, Malaysia on Sept. 14, 2012.

Catherine, Duchess of Cambridge, and Prince William during Day 6 of the London 2012 Olympic Games at Velodrome, England on Aug. 2, 2012.

Waxworks figures of Catherine, Duchess of Cambridge, and Prince William at Madame Tussauds in London revealed on June 22, 2012.

Prince William and Kate, the duchess of Cambridge, pass along The Mall as part of a four-day Diamond Jubilee celebration to mark the 60th anniversary of Queen Elizabeth's accession to the throne on June 5, 2012.

Catherine, Duchess of Cambridge, onboard the Spirit of Chartwell during the Thames Diamond Jubilee Pageant in London. Queen Elizabeth II and the Royal Family sailed on the ceremonial barge at the center of a 1,000-boat pageant on June 3, 2012.

Prince William, right, with Kate, the duchess of Cambridge, and Prince Harry, during a reception before Queen Elizabeth II's Sovereign Monarchs Jubilee lunch at Windsor Castle on May 18, 2012.

Prince William and Kate, the Duke and Duchess of Cambridge wave from their plane before departing from their cross-Canada tour in Calgary, Alberta, Canada on Friday, July 8, 2011.

Prince William and Kate, the Duke and Duchess of Cambridge, arrive at Los Angeles International Airport in Los Angeles on July 8, 2011.

Prince William and Kate, the Duke and Duchess of Cambridge push the button to officially start the Calgary Stampede parade in Calgary, Alberta, Canada on Friday, July 8, 2011.

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge, visit Province House in Charlottetown, Canada on July 4, 2011.

Prince William and Kate, the Duke and Duchess of Cambridge, look on during a private reception at the British Consul-General's residence in Los Angeles on Friday, July 8, 2011.

A photo from the Clarence House Press Office shows Prince William and Kate Middleton before their wedding which was held at Westminster Abbey on April 29, 2011.

Prince William arrives for Christmas Service at St. Mary's church on the grounds of Sandringham Estate, the Queen's Norfolk retreat, England, Sunday, Dec. 25, 2011.

This is one of two official portrait photographs Prince William and Catherine Middleton have chosen to release to mark their engagement, taken in the Council Chamber in the State Apartment in St James' Palace on Nov. 25, 2010.

Britain's Prince William and Kate Middleton during a photo call to mark their engagement, in the State Rooms of St James's Palace, central London on Nov. 16, 2010.

Prince William and Kate Middleton during a television interview recorded and aired on the day they announced their engagement, Nov. 16, 2010.

Kate Middleton with her Prince William, unseen, during a television interview recorded and aired on the day they announced their engagement on Nov.16, 2010.

Prince William and

Prince William and Kate Middleton pose for the media at St. James Palace in London after announcing their engagement on Nov. 16, 2010.

Britain's Prince William talks to soldiers before a remembrance day ceremony at Camp Bastion in southern Afghanistan on Nov. 14, 2010.

Prince William talks to members of the Royal Irish Regiment, before a Remembrance Day ceremony at Camp Bastion in Afghanistan on Nov. 14, 2010.

Prince William hands out silver and gold pins to sailors at HMNB Clyde naval base in Faslane, Scotland on Oct. 28, 2010.

Prince William and Kate Middleton leave the wedding of their friends Harry Mead and Rosie Bradford in the village of Northleach, England on Oct. 23, 2010.

Prince William poses in front of a Griffin helicopter during a photo call at RAF Shawbury in Shawbury, England on June 18, 2009.

Prince William and his girlfriend Kate Middleton after his graduation ceremony at RAF Cranwell air base in Lincolnshire on April 11, 2008.

Prince William and Kate Middleton watch the England against Italy Six Nations rugby match at Twickenham stadium in London on Feb. 10, 2007.

Kate Middleton and Prince William on the first day of the Cheltenham Race Festival in Gloucestershire on March 13, 2007.

Prince William and Kate Middleton watch the action during the RBS Six Nations Championship match between England and Italy at Twickenham in London on Feb. 10, 2007.

Prince Charles and William leave William's graduation ceremony in St Andrews, Scotland on June 23, 2005.

Prince William and Kate Middleton after their graduation from St. Andrews University in Scotland on June 23, 2005.