Kate Middleton was just one of the guys in London on Thursday!

The Duchess of Cambridge -- who was a field hockey player in school -- proved she's not just a gorgeous gal in pretty clothes during her appearance with Princes William and Harry at the Coach Core (a sports coaching initiative for 16-19-year-olds) launch. Dressed in a belted Hobbs "Wessex" dress and sporting Pied-a-Terre wedges, the 30-year-old rolled up her sleeves to partake in the school's sports just one day before the opening ceremony of the Summer Olympics.

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For her first sport, Kate challenged some players to a table tennis match. A witness tells Us Weekly, "The coach instructed her to 'Get low!' and she gave it her best shot and even scored a few points!"

While Prince William, 30, spent time on the soccer field, his younger brother, Prince Harry, 27, hit the basketball court. After wrapping up her table tennis match, Kate shed her shoes to referee a judo match -- and made sure to put on her game face.

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As the royal trio were wrapping up their trip, Prince William gave a cheeky speech on how sports have played an important role in their lives.

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"Watching me on the football [soccer] field is never a pretty sight -- the expression 'giraffe on ice' springs to mind. However it is marginally less embarrassing than seeing my brother cheat his way to becoming the fastest man on the planet," he joked, referring to Harry's race against Usain Bolt during his trip to Jamaica in March. "Catherine, on the other hand, with a tennis racquet or a hockey stick is something to behold and be aware of."

This article originally appeared on Usmagazine.com: Kate Middleton Plays Ping Pong, Soccer with Princes William and Harry