Elton John and David Walliams flash bums at Simon Cowell

Simon Cowell was left shocked after Sir Elton John and David Walliams flashed their bums at him while enjoying a holiday on the French Riviera.

The music mogul got a full view of the 'Rocket Man' hitmaker and the comedian's bare behinds in St Tropez when each party's boats passed each other on the French Riviera.

David - who was with his wife Lara Stone on holiday - shouted across to Simon: "I've got something for you."

He then exposed his backside followed by the 65-year-old singer, and the 40-year-old TV star blew a kiss to the 'X Factor' boss and shouted back: "Love you Simon."

David later took to his twitter account to reveal the pair had shown their butts to his 'Britain's Got Talent' co-star.

He wrote: "I just mooned Simon Cowell. From a boat. That is true".

"And then someone a million times more well known than me mooned Simon Cowell too."

David and Simon have also been having fun with a mystery dog this week, and the comedian posted a picture on his twitter account of the pooch climbing on the music mogul's face.

In a message accompanying the image, he wrote: "A dog sitting on Simon Cowell's face."

Elton has been spending time with his husband David Furnish and their 19-month-old son Zachary, as well as their friends, actor Neil Patrick Harris and his partner David Burtka and their 21-month-old twins Gideon and Harper, in St Tropez this week.