Keira admits her love of stripping off for photos

Her performance in Atonement has made her an early tip for an Oscar, but as Keira Knightley's fame has increased so have her complaints about media intrusion into her life.

Yet far from shunning the limelight, the 22-year-old is starring in an advertising campaign for fashion house Coco Chanel, in which she appears naked – covering her breasts with a bowler hat.

In an interview in the latest edition of Vogue, Miss Knightley admits she is trying to 'have her cake and eat it' by taking her clothes off for advertisers while at the same time demanding privacy.

The new pictures follow a similarly revealing shoot for the cover of Vanity Fair magazine last year.

Miss Knightley, who has in the past been vociferous in her condemnation of photographers pursuing her in public, was challenged during the Vogue interview on the apparent contradiction between her complaints about intrusion and undressing for a billboard poster.

She replied: 'Of course I want to have my cake and eat it. Who doesn't want to have their cake and eat it? Show me that person.'

And the actress defended the advertisement, saying it was 'something to show the grandchildren', adding that posing for the pictures was a way of overcoming her own 'inadequate' feelings about her body.

Miss Knightley has in the past been brutally honest about her body shape, particularly her lack of cleavage. She has now revealed her angst at being criticised for being too thin.

'When I was 17, 18, 19, I felt incredibly insecure,' she told the magazine. 'I went through a period of thinking I looked weird and too skinny, and that's ten times worse when you're being written about.'

She also spoke of how life on a film set – where everything is done for you – can place extra pressures on young actresses, particularly in the glare of publicity.