The Pirates of the Caribbean star reteamed with her Atonement director Joe Wright for the literary masterpiece, with Knightley playing Karenina, a married woman who has an affair with a soldier.

Greta Garbo and Helen McCrory have previously played the part - but Knightley was keen not to pay close attention to their scenes.

She tells Interview magazine, ""I saw a couple of versions ages ago. I've seen the one that was on TV in England with Helen McCrory playing Anna, and she's wonderful.

""I also saw the Greta Garbo version, but years and years ago. I didn't want to see it again just before I played the part because I thought if I did something similar that I would want it to be an accident, not because I've nicked (stolen) it.""