Pippa and James gear up for cycling challenge

Pippa Middleton and brother James Middleton are preparing to ride across the United States for charity on June 14.

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The 30-year-old socialite and her 27-year-old brother will be part of an eight-person cycling team embarking on a 3,000-mile journey from Oceanside, California, to Annapolis in Maryland to raise money for charity Race Across America cause.

The cause is in memory of their teammate James Matthews' late brother, Michael, who died in 1999 following a deadly descent from Mount Everest.

While this is undoubtedly one of Pippa's most grueling challenges yet, this isn't the first time she's tested her endurance.

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The younger, sporty sister of the Duchess of Cambridge has completed a 56-mile cross-country skiing race in Sweden in March 2012.

The previous year she took on a Highland Cross Challenge in Scotland, running and cycling 50 miles coast-to-coast.

Pippa competing in the Blenheim Triathlon in 2011. Source: Getty Images

She's also voiced her interest for other sports, including sailing, swimming, and particularly tennis, which has seen her regularly attend tournaments including Wimbledon and The French open.

The Duchess previously spoke of her affinity for cycling in a column for the Daily Telegraph.