Keira Knightley was amazed when director Tony Scott asked her to chose a body double during filming for new movie Domino.

The Pirates Of The Caribbean beauty refused to bare her own bottom for a lapdancing scene - so Scott paraded three girls in front of Knightley and she chose the most suitable posterior to take her place.

She says, "Tony brought three girls in to choose from. It was hard not to laugh, but I didn't want to offend anyone.

"I decided to be very business-like. They all had very nice bottoms and I chose one."