Mary-Kate and Ashley Olsen Throw Olympic-Themed Birthday Party—Find Out Which Sister Won Top Prize!

Guests are treated to food, games and fireworks in the Hamptons

By Mike Vulpo Jun 14, 2015 8:48 PMTags

On an island in the sun, Mary-Kate Olsen and Ashley Olsen will have some serious fun!

When the fashion designers turned 29 Saturday afternoon, they didn't just celebrate by themselves. Instead, they invited their closest friends together for an Olympic-themed birthday party in the Hamptons.

Using the hashtag #OlsenOlympics, guests gave fans a preview of the day's festivities that included dunk tanks, fireworks and obstacle courses. But before partaking in any of the activities, friends had to wear either Team Ashley or Team Mary-Kate T-shirts.

Without further ado, let the competitions begin!

PHOTOS: More celebrity twins

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From the looks of things, Ashley and her group definitely came out on top as one friend posed with the winner. "Champions," Jared Seligman wrote on Instagram. #TeamAshley #OlsenOlympics #Twinning #SorryMK."

He later wrote, "Happy Birthday my beautiful MK. You will always be a winner in my book...Except today. #OlsenOlympics #WereNumber1."

As the ladies turn one year older, the entrepreneurs will continue to work hard in their respective careers. 

While they won't be appearing in the Fuller House series on Netflix, both ladies plan on growing their fashion empire that includes Elizabeth & James. They also will be receiving inspiration from some other Hollywood stars.

"Gigi Hadid," Mary-Kate told Miss Vogue U.K. when asked who her current style icon was. "Whether she's on the carpet or on the street, she always looks effortless and cool."

Ashley added, "Amber Heard. She balances her bohemian look with a touch of edge."

A photo posted by Yale Breslin (@yalebreslin) on