Actress Keira Knightley has refused to allow any airbrushing to be done on the publicity pictures for her new movie, 'The Duchess'.

Studio execs wanted to make the slight actress appear shapelier, but Knightley snubbed the proposal, insisting that no cleavage be drawn onto the pictures.

A source said: "She has insisted that her figure stay in its natural state. She is proud of her body and doesn't want it altered."

The 23-year-old star was famously enhanced in the posters for her 2004 film 'King Arthur'. In Europe the posters showed her in her natural state, while in America the posters were enhanced to give her an ample bosom.

Knightley said her cleavage in the 2004 film was achieved using make-up.

No such illusion was employed in 'The Duchess', though, as the source added: "She looks flat-chested in the whole movie."