Mia Wasikowska struggled on Alice

Mia Wasikowska admitted she found working on 'Alice In Wonderland' difficult because of the extensive use of green screen.

Mia Wasikowska found 'Alice in Wonderland' to be "the most difficult kind of acting".

The Australian actress took on the titular role in the Tim Burton-directed film, but the use of green screen technology on the movie - which has grossed over $1 billion at the international box office - meant she often felt "lost".

She said: "It was the best education - seeing how Tim worked, learning from him and absorbing the whole environment.

"The green screen was very challenging as you can't judge what's happening. You rely on people telling you what kind of atmosphere you are in. It's the most difficult kind of acting. You have to trust the director because you can definitely feel lost."

Despite the troubles, the young star felt it helped her learn a lot about working in the movie business.

She added in an interview with Total Film magazine: "It was exposure on a level I'd never experienced before, which is a positive thing."