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Representing Britain! Pippa Middleton is the only girl on a team of eight Brits racing the 3,000 miles across America in a charity bike race. The younger sister of Duchess of Cambridge Kate Middleton is participating in the Race Across America, decked out in spandex biking gear with the British flag printed on the front.

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Her bearded brother James Middleton will be racing on her team. The pair were photographed training for the grueling task on Saturday, June 14. Pippa's backside, which became famous after she served as the maid of honor at her sister's 2011 wedding, was on display in her tight biker shorts.

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The race has been going on for 32 years and in that time, fewer than than 200 individuals have successfully completed the event.

PHOTOS: Pippa and James at the Queen's last birthday

As Pippa, 30, got ready to ride, her sister Kate attended Queen Elizabeth II's 88th birthday celebrations with her husband Prince William and her brother-in-law Prince Harry at the Trooping the Colour parade.