Trance star Rosario Dawson took to the red carpet in a red gown by British designer Jenny Packham at the movie's premiere in London on Tuesday night.

The actress chose a heavily embellished floor-length evening dress which featured cut-out detailing and draping at the back.

Dawson was joined on the red carpet by the film's director, Danny Boyle, and co-stars James McAvoy and Vincent Cassel.

Dawson plays a hypnotherapist in the twist-filled thriller and underwent hypnosis in preparation for the role.

Speaking to the Press Association about hypnosis, she said: "I think it works actually, quite well. I didn't have anything like cigarettes to quit or anything like that.

"But I remember I went in and gave her an idea of what I wanted to work on in the session. And I lay down and she put a blanket over me because when you go into a trance state it's sort of like being in between sleep and awake, so your body thinks it's falling asleep. So I got cold and then I relaxed and I went along with her voice and it was really comforting. My body did those little spasms that it does when you're falling asleep.

"And then I woke up and she said, 'I know you said you wanted to work on this, but you reacted to this, this and this'. And I was like, 'How can you know all that?!' And she said my foot was kicking when she asked me about a certain thing.

"So it's actually quite interesting that your conscience will reveal itself, and if you're trained to read that, people give a lot of tells. It's almost like poker. We think we're hiding things, but we're not.

"So it was really great for me to experience that, because the premise of the film is that hypnotherapy works on such a strong level.

"So it was really necessary for me to believe that, and having been through that I gained a lot of respect for the profession, I have to say."

Trance opens in Irish cinemas on Wednesday March 27 – watch out for interviews with the movie's stars and director Danny Boyle next week on RTÉ TEN.

L-R: Danny Boyle, Rosario Dawson, James McAvoy, Vincent Cassel