was "pushed" to the limit filming 'The Girl with the Dragon Tattoo'.
The 26-year-old actress - who portrays main character Lisbeth Salander in the English language adaptation of the Swedish film series - was "shocked" by the physical and emotional challenges required to shoot the movie, which was filmed in Sweden during the winter.
In an interview with the Daily Telegraph newspaper, she said: "I had prepared myself and I knew how emotionally and physically challenging making 'The Girl with the Dragon Tattoo' would be, but the whole project really pushed me. The physical challenge was probably even more shocking than the emotional, because there were lots of days that we were doing stunts, with many takes, over and over.
"It was an amazing experience and I know that I have learnt so much. I am just not quite sure what that is yet."
But the brunette star became "frustrated" with director David Fincher during the two-and-a-half month audition process, compared to her "easy" try-out for David for 'The Social Network'.
"The whole process was quite frustrating towards the end. I felt like, 'You either think I have proved I can do this to you or you don't, but at some point I have to move on with my life.' It was a really long, hard process."