And they're off!
Pippa and James Middleton have started their trek across the U.S., pedaling past the starting line on Saturday in San Diego, California.
And while sister Kate, brother-in-law Prince William and their nephew Prince George weren't in the cheering crowd to see them off, the sibling set brought a piece of their homeland to the event with their patriotic cycling suits.
The Middletons – along with their team of eight cyclists, including good friend James Matthews – will bike 3,000 miles across 12 American states in just eight days to reach Annapolis, Maryland, all in support of Matthews's late brother, who died in 1999 during a descent from Mount Everest.
The buzzed-about charity event, Race Across America, will also benefit the British Heart Foundation, of which Pippa is an ambassador.
With her own sponsorship page, she is hoping to raise even more money by auctioning her bespoke bike on eBay when the race is over.
Pippa's summer plans may also include competing in the 6.5-km Bosphorus Cross-Continental Swimming Race on behalf of the same foundation.
In a statement released by the British Heart Foundation, she said, "I was shocked to learn that nearly three times more women die from coronary heart disease than breast cancer. I'm passionate about raising awareness amongst women of this killer disease and I look forward to working with the BHF to highlight to women the risks of heart disease and importantly, how they can reduce them."
Axelle Woussen / Bauer-Griffin
Reporting by SIMON PERRY