Once Rosamund Pike was cast in Gone Girl, she landed a role that Oscar winners such as Reese Witherspoon, Natalie Portman and Charlize Theron had been coveting. Although the Brit built a busy career with supporting roles, Gone Girl is her first lead—and a juicy one at that. Pike plays Amy Dunne, who disappears under strange circumstances and whose husband (played by Ben Affleck) falls under a cloud of suspicion. Amy’s motivations become just as puzzling as her absence later in the film, something that Pike says made doing early press on the film challenging. “I’ve been hiding so much of the character for so long because I haven’t been allowed to talk about her devious side,” she explains. Pike recently spoke about the release she feels in finally being able to talk about Amy, as well as the thrill of playing her.

How did the script for Gone Girl first come to you?

I had the cryptic message that (director) David Fincher wanted to talk to me about something. David moves in very mysterious ways, and he tends to leave agents in the dark, which is very nice for the actor because you have an unusually protected line of communication once that line is open. So we started having these very long Skype conversations as I read the book. He was monitoring my reading reactions, and we talked about all kinds of things. I wasn’t quite sure what this process was, and then you sort of feel like you’re being intensely scanned by a very high-processing computer, which is a bit how David’s brain can come across sometimes. Eventually we started moving closer to a meeting in person, as opposed to pixilated versions of ourselves on Skype.

Did that also serve as the research process for you?

I don’t think the research is ever done. (Amy) is a constantly evolving creature. You’re looking for injections of things: Whether it’s watching a particular woman deal with something at a grocery store or whether it’s reading a new book on psychology, looking at blogs on the Internet—it’s amazing (to see) the personality types on a shared forum. I mean, there are Amys out there blogging. Often when you’re dealing with socially marginal or unpleasant personality types, we usually like to feel, “Oh, that’s them and this is me,” so that you can feel removed. Where writer Gillian Flynn places her characters is always in something that one can identify with in part, and then she shows you the true colors. It’s a very unsettling experience because there’s a much smaller degree of separation between wrong-doers and right-doers than we like to suppose.

Was it draining to play a character with so many highs and lows?

Oh, no. It’s thrilling. I certainly relish the chance to play a woman who didn’t have to conform in any way ever to expected behavior or desirable behavior or attractive behavior. Sometimes she does by choice and people are seduced by her seeming like the victim and seeming vulnerable and fragile. Most of it, we learn, is invented. She’s trained by her parents to know how to appeal to an audience through “Amazing Amy.” And then in her adult life she’s trained to know how to appeal; then at a certain point we see her shed those layers and say, “Look. Here I am. Like me now?” For six months, I’ve basically been keeping up the pretense of Amy being just one thing: the missing victimized wife. So there’s been a release now in being able to express the other side. I’d been harboring her since we stopped filming and only now I’m saying goodbye.

What kind of rehearsal period did you have for the film?

We had about a month of sitting in a rehearsal room. Gillian Flynn was there, tailoring scenes to the actor that she found in front of her, which was really exciting. Sometimes you realize that you don’t need a line because it can be done with a look, then getting the rhythm of certain actors where they play to their strength. You look at someone like Carrie Coon, who had such great delivery and captures Gillian’s wit so well. It was great because Gillian could embrace her own voice, and Carrie knew exactly how to deliver it. The only bit of stage rehearsal that was done in advance was the scene with Neil Patrick Harris in his bedroom. That was the only thing that was in any way set in stone.

Have you been surprised that a few people have called the film misogynistic?

I haven’t really been aware. I know that in the past Gillian’s books have been accused (of that). So many times, when the woman is being rescued or saved, if she’s not a nurturing, maternal type then she’s in some way less of a woman—absolutely not in my view. Amy makes mistakes and you might not admire her, but she’s utterly true to herself. We actually see a woman who’s been performing her whole life and suddenly we see the true (person), which stems from some very deep-rooted anger. And we are in a culture that doesn’t really embrace female anger or allow an outlet for it without a woman seeming hysterical or shrill. What’s so great about Gone Girl is the conversations it provokes. It’s really exciting, more so than anything I’ve been a part of.

Rosamund Pike photographed by Mark Mann