Keira Knightley struggled with dancing

Keira Knightley was upset she couldn't pick up the dance moves in 'Anna Karenina'.

The British actress - who plays the title role in the Joe Wright-directed film - found it frustrating when she couldn't pick up the intricate and elaborate routines in the film, whereas her co-star Aaron Taylor-Johnson had no problem at all.

She said: ''I think I'm quite good at picking things up and I found this impossible and Aaron could just do it in about five seconds. It took a really long time.''

However it was not all easy for Aaron, as Joe revealed he was sick during the shooting of the dance scenes.

He added: ''One day when Aaron was actually ill, and there's a bit in the dance when he has a really red face, he was trying not to be sick.''

Much of the film takes place in a theatre which constantly changes scenery, despite Joe thinking he was a much more ''on location'' kind of director.

Hesaid: ''I always thought I'd be the kind of filmmaker who dealt predominately with real locations but I find more and more that I like creating spaces in which to play out our dreams. Often there are quite critical limitations put on filming in these locations, so it was interesting.''