Keira KnightleyKeira KnightleyFor many people, spending the day browsing a line up of pert bottoms would be a damn sight better than sitting at a desk in a dull office.

And in true Hollywood style, that is exactly what Keira Knightley had to do when she decided her butt wasn't up to filmic exposure.

Whilst filming her latest film, the 19-year-old actress opted for a bottom double - claiming that her behind wasn't perfect enough, reports the Daily Mail.

"We had an audition. I was in an office and women came in and started stripping. They had fantastic bums and it's at that point you go 'OK, unless your bum looks like that, don't show it on film.'

"I don't have a bum like that so it's not in the film," she admitted.

Instead a former ballerina from Romania got the gig... Roberta Lorince, 28, who works in a naked review in Las Vegas was paid £550 a day to stand in for Keira's nude scenes.

The British actress also opted out of doing lap dancing scenes in the movie - despite visiting strip clubs and taking classes.

"I could do the top half, but not the bottom," she explained. "I got too scared and got a double. I couldn't bend in the way you're meant to bend."

The film in question is Domino, which tells a fictionalised account of model Domino Harvey who ended her catwalk career to track down criminals - in the movie Keira has to work as a stripper when she goes undercover.