(digitalspy.co.uk) - Keira Knightley banned movie bosses from digitally enhancing her breasts in a new film, say reports.According to the Daily Mail, the actress, 23, insisted that her figure be left alone by producers in period drama The Duchess."She is proud of her body and doesn't want it altered," said a source. "But she looks flat-chested throughout the whole movie."Knightley plays Georgiana, the Duchess of Devonshire in the Saul Dibb-helmed project. The film is scheduled for release on September 5.