Everyone involved in Ghost in the Shell was quick to defend her casting, including Mamoru Oshii, director of the original Japanese animated film version. For her part, Johansson says, "I think when you have a character that's so beloved, people have a lot of opinions. I try to kind of clean the slate and really follow my instincts with the character and hope that I give the character as much integrity as people expect. I certainly would never presume to play another race of a person. Diversity is important in Hollywood."

Scarlett Johansson at the Ghost In The Shell premiereScarlett Johansson at the Ghost In The Shell premiere

And now with the film in cinemas, she adds, "I think it'll be up to the audience to judge if I'm the right person to play this part. I think in this case it was my sympathy for this character's experience that made me feel I was capable to play this role. And you know, of course I love to do the physical part of it. It's always fun for me. It's challenging to learn more skills and just get better at my job."

More: Read the review for Ghost In The Shell

Johansson feels that the film taps into universal themes. "I think we're very used to the idea of the future in an armageddon context or a post-apocalyptic kind of idea. Either that, or everything's kind of digitised and computerised and clean," she says. "For this movie, Rupert [Sanders, the director] described it to me as cities built on cities and the abundance of waste. It's a kind of collage of cultures, and it's sort of identity-less in that as a whole melange of different kinds of textures and colours. It's really rich, the depth of this movie is amazing. I found the sets so incredibly detailed."

Diving into her role as Major, Johansson enjoyed playing a character struggling to separate the truth from fiction within her own memories. "This experience has been like nothing else I've ever had before," she says. "It's really been all-encompassing and I feel I've taken on this character in a way that was very unexpected. It's hard to shake for me, and I hope the audience shares the same compassion that I have for this character. And I hope they willingly go on this ride with me, because it's a ride for sure!"

Watch the trailers for Ghost In The Shell: