(Cover) - EN Showbiz - Natalie Portman says she prepared for Black Swan by being boring.

The pretty actress stars as disturbed ballerina Nina Sayers in the thriller, and the performance looks set to win her an Oscar nomination. Natalie was working on fantasy film Your Highness before Black Swan and the superstar admits the experience was hardly debauched.

Right before Black Swan I filmed Your Highness in Belfast, so that was the peak of my pre-movie training, the 29-year-old told Cover Media. So I was with the most fun people, in the most fun country, not having any fun. It was very sad.

Natalie was on a strict diet in preparation for Black Swan and could not let her hair down too much by going out partying with her co-stars. Even though she regrets not tasting the local food and drink, she loved being able to take in some breathtaking scenery.

I was the boring schoolgirl with all the cool guys hanging out, she joked. There was no drinking, not a lot of eating... I guess I got to see some of the countryside though which was really, really beautiful, because that you can do sober.

Natalie revealed that she was constantly getting injured on the set of Black Swan due to some of the awkward manoeuvres she was expected to perform. One of these injuries actually impacted on her performance for much of the film.

There were constant foot things and strained muscles, but the worst thing was the dislocated rib which happened during a lift, she explained. Its where one rib goes under another rib, and it just feels like a stitch. It happened in the halfway point, so for the second half of the film I couldnt really take a deep breath, but they just changed the lifts from then on so theyd be under my armpits instead of around my ribcage.

Natalie says one of the best things to come out of her time working on the film is her newfound respect for ballerinas. She thinks their ability to continue through overwhelming pain proves an ultimate dedication to the cause.

It was good to understand what real dancers go through, because theyre constantly dancing through very difficult injuries, she added. It often happens right when they get promoted because they work really hard to get promoted and then when they get promoted they have bad injuries because theyve been dancing so hard, but they dont want to give up their spot because theyll be replaced so theyll just dance with a sprained ankle or with a torn something, or some really extreme thing that would usually have people benched.

Theyll dance beautifully on stage and then theyll limp off into a bucket of ice, its pretty shocking.

Black Swan is released in the UK on January 21. (C) Cover Media