Mila Kunis has hit back at claims that Natalie Portman didn't perform her own dance moves in 'Black Swan'.

The Oscar-winning actress has recently been the centre of controversy after her double Sarah Lane claimed she did 90 per cent of the brunette beauty's ballet Steps in full-body shots.

However, Natalie's co-star Mila has defended her, saying that although the star didn't perform every intricate move, she "danced her a** off".

She explained: "I think it's unfortunate that this is coming out and taking attention away from [the praise] Natalie deserved and got.

"She'll tell you [that], no, she was not on pointe when she did a fouetté. No one's going to deny that. But she did do every ounce of every one of her dances."

The Ukrainian-born actress added that Sarah was simply on standby for moves Natalie couldn't perform herself.

She told Entertainment Weekly: "[She] wasn't used for everything. It was more like a safety net. If Nat wasn't able to do something, you'd have a safety net. The same thing that I had - I had a double as a safety net. We all did. No one ever denied it."