(Cover) - EN Showbiz - Mila Kunis has revealed her struggle to get as skinny as possible and learn ballet for her role in Black Swan.

The actress portrays Lily in the movie, a rival ballerina to Natalie Portmans character Nina.

The American actress has admitted the preparation for the film was tough, especially on her body, as she had to lose weight at a fast rate and learn expert ballerina moves at the same time.

The preparation was get as skinny as you possibly can as fast as you can and then learn to get on point while doing it, she explained to MTV.

The 27-year-old actress explained she was put through a gruelling dance training regime by a 20-year-old woman.

Milas trainer was so strict that the brunette actress was only allowed one day off for her birthday in six months.

So I got the part lets say on a Wednesday, Thursday morning I went into the ballet studio in LA with Alexander Backer who was my ballet instructor who is 20-years-old at the time and I think already broken her back and fractured ribs and things anyway, went in there and started working with her for seven-days-a-week, five-hours-a-day and was put on a 1200 calorie diet I think for a total of five to six months. But I did get one day off it was my birthday... Mila said. She never gave me a break she was 20 [years-old] and she kicked my ass. (C) Cover Media