The 41st annual Hampton Classic Horse Show came to a close Sunday in Bridgehampton after a celebrity-drenched day that included the richest purse in the show’s history.

Madonna, twin actresses Mary Kate and Ashley Olsen, and former New York City Mayor Mike Bloomberg were among those attending the event, which has evolved into a must-go, end-of-summer social affair for Hamptons VIPs.

The Classic was once a small informally judged horse competition, but has developed international recognition as one of the premier shows in the world of equestrian competition. It attracts an estimated 60,000 spectators throughout the week.

The eight-day event includes hunter and jumper competitions, featuring six show rings, and riders of all skill levels, and as young as 2 years old competing for prizes.

Sometimes referred to as “the Hollywood horse show,” the Classic’s closing day also drew actor Kyle McLaughlin, television host James Lipton, designer Kelly Klein, and former models Christy Turlington and Brooke Shields — despite mixed weather warnings Sunday related to Tropical Storm Hermine churning in the Atlantic Ocean east of the Hamptons.

“It was a hugely successful day,” event spokesman Marty Bauman said. “All the scares of the weathercasters did not come to pass.”

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The classic culminated in The Grand Prix competition, which was moved up an hour to 1 p.m. in an effort by show organizers to beat any potential weather complications.

Richie Moloney, an Irish national who rides out of Riverhead, won the Grand Prix, which had a $300,000 purse — the largest in Classic history, Bauman said.

With a first-place time of 39.57 seconds, Moloney will take home the largest portion of the purse: $99,000.

Moloney also won the $30,000 Longines Rider Challenge by having the highest cumulative score of any rider in his class competing in this year’s show. It was his third time winning the challenge in four years.

Katherine Strauss, 18, of Southampton, won the Campbell Stables Show Jumping Derby, the biggest contest of the week for junior and amateur riders.