'Atonement' star Kiera Knightley says she is not happy with her body, despite her slim figure.

Kiera Knightley

The 26-year-old actress said that she was once so unhappy with her body that she used a body double for her 2005 film "Domino", reported Daily Mail online.

"I have this policy in films where I say, 'You can have the top half but you can't have the bottom half', and it kind of works quite well.

And there was this scene in Domino where I was meant to do a bit of a strip tease and a dance with a thong on.

I was just like, 'It's not going to happen'. And so I said, 'Could you get me a bottom please?'," Knightley said. The actress will be next seen in the Freudian drama "A Dangerous Method" opposite Michael Fassbender.