Teresa Palmer transformed herself into a "warrior woman" to play tough alien Number Six in sci- fi adventure I Am Number Four.
The Take Me Home Tonight beauty stars opposite Alex Pettyfer and Dianna Agron in the film about a group of young aliens who hide on earth after their planet is destroyed.
Teresa revealed: "I'd dabbled in kick-boxing lessons here and there, but I really had to transform myself into this warrior woman and it was no mean feat!"
She went on: "It was so foreign to me, I'd never done anything like that before, especially not for a film role.
"I was doing five or six hours of training a day, it was really intense.
"I really enjoyed the experience though, I love pushing myself physically as well as mentally.
The 25-year-old Australian said she wanted to be the best for director D.J. Caruso.
She revealed: "I asked the stunt team to treat me as if I was a stunt woman, not as though I was an actress who needed a stunt double to come and do the work for her. That way D.J.had the freedom to be able to shoot me at any angle without having to hide a stunt double's face.
"I was black and blue from all of the stunts, but it was well worth it."
:: I Am Number Four is out on Disney Blu-ray and DVD from 20 June.