This weekend the Duchess of Cambridge's siblings, Pippa and James Middleton, will compete in Sweden's annual Vasaloppet cross-country ski race to raise money for charity.
According to the race's official website, the Vasaloppet has its roots in royal history, commemorating future Swedish king Gustav Eriksson Vasa's escape on skis from the soldiers of Denmark's King Christian II. Today's king, Carl XVI Gustaf, and two of his children, Prince Carl Philip and Princess Madeleine, have participated in the race in years past.
UPDATE: Crown Prince Frederik of Denmark will also participate in Vasaloppet this year.
MARCH 4 UPDATE: Pippa and James Middleton have completed the race, and you can see photos here.
Photo of Pippa Middleton © Press Association. Source: The British Monarchy