Natalie Portman was in a state of "inner terror" during her lesbian kiss with Mila Kunis.

The screen beauty - who locks lips with her pretty co-star during their new film 'Black Swan' - admits she was petrified of locking lips with a woman for the camera.

She said: "I was terrified. At the moment I lived in a state of inner terror."

Natalie also worried the lesbian sex sequence is overshadowing the plot of the film and fears it will make her be taken less seriously as an actress.

She explained: "Nudity is something absolutely natural and I'm not prudish - but in a film it can be distracting. Doing 'Black Swan' I couldn't say no. The project is a huge opportunity for me to show a new me. I can't always play the nice mothers. My other problem is that single pictures are being taken out of context and put on the internet."

A preview clip of the movie - which is about the highly competitive world of New York ballet and follows Natalie's veteran ballerina character who finds herself locked in direct competition with a mysterious rival dancer - became an internet hit when it was uploaded to the web, including scenes of the women kissing.