All eyes were on the leather-clad rider as he roared up to Cowarth Park club in Ascot, Berkshire, atop a revving black motorbike. It wasn't until he removed his crash helmet that many spectators realised the mystery man was in fact Prince William.
The 27-year-old royal looked more king of the road than future king as he arrived on his powerful Ducati motorbike to play in a charity polo match with his younger brother Prince Harry.
There was a clue to his identity, however, in his patriotic knee sliders – which bore the design of the Cross of St George. The reinforced pads are used to protect bikers' knees if they touch the ground when cornering at high speed.
Wills is a keen and accomplished biker who has been riding off road since he was eight. Last year he put his skills to use for a good cause, joining Harry on a motorcycle trek across South Africa to raise funds for his brother's charity Sentebale.
He often takes his £15,000 bike - which is considered the ultimate high performance two-wheel vehicle and can reach top speeds of 180mph - out for a spin at weekends, mainly around his father's Highgrove estate and the country roads of Gloucestershire.
"I don't know what it is about bikes, but I've always had a passion for motorbikes ever since I was very small. I used to do a lot of go-karting when I was younger and then after that I went on to quadbikes and eventually motorbikes," he once said.
"It does help being anonymous with my motorcycle helmet on because it does enable me to relax," he continued. "But I just enjoy everything about motorbikes and the camaraderie that comes with it."