Knightley Still Waiting On My Fair Lady Confirmation

The Pirates of the Caribbean star is the favourite to take Audrey Hepburn's iconic role in the update of the 1964 musical, based on George Bernard Shaw's comedy of manners Pygmalion.

But Knightley is adamant a final casting decision has yet to be made - so she's keeping her "fingers crossed".

However, if she does become the leading lady, she is keen to try and hit the high notes - and sing all the musical's songs without any help.

She tells MTV.com, "It's an interesting prospect, but there's nothing concrete. Fingers crossed on that one (landing the part).

"I like doing things where I'm not sure if I'm going to be able to do them or not (singing). I think you have to push yourself. You have to admit you're going to fail at some point. You've got to try. Like with anything I do, there's always a part of me that says, 'I can't do that. This is going to be the one where I fall on my face completely.' It would be exciting to try it."