From Heidi Klum as Jessica Rabbit to Katy Perry as Hillary Clinton, these are some of the most outrageous and memorable costumes celebrities have donned throughout the years.
Savannah Guthrie and Matt Lauer
Savannah Guthrie as Kenny Rogers and Matt Lauer as Dolly Parton perform during NBC's "Today" show at Rockefeller Plaza in Manhattan on Tuesday, Oct. 31, 2017.
Heidi Klum was unrecognizable as Michael Jackson from his "Thriller" video during her 18th annual Halloween Party, held at the Magic Hour Rooftop Bar & Lounge on Tuesday, Oct. 31, 2017.
Bette Midler reprised her role as Winifred Sanderson from "Hocus Pocus" for her Halloween costume in 2016.
Heidi Klum is known to go all out for Halloween; this iconic look (an aged version of herself) was her costume in 2013.
While Miley Cyrus was dressed up in another iconic costume at the MTV Video Music Awards, Perez Hilton dressed up as Miley Cyrus at the 2013 MTV VMAs.
NBC's "Today" anchors dressed up as the Kardashian clan for the 2011 Halloween episode. Melissa Francis was Kourtney Kardashian, left, Jenna Wolfe was Khloe Kardashian, Lester Holt was Bruce Jenner, Amy Roebuck was Kim Kardashian and Janice Huff was Kris Jenner.
Fergie dressed up as a contestant from TLC's reality show "Toddlers & Tiaras" for Halloween in 2011.
During a Halloween party in 2009, Perez Hilton dressed up as Lady Gaga complete with a hair bow, which was her signature look at the time.
For her ninth annual Halloween party, Heidi Klum dressed up as the Hindu Goddess Kali in 2008.
Heidi Klum dressed as Betty Boop for her third annual Halloween Party in 2002.
Arnold Schwarzenegger and Jamie Lee Curtis
Arnold Schwarzenegger and Jamie Lee Curtis dressed up as Dr. Ken and Nurse Barbie for a Halloween charity event on Oct. 27, 2001.