IW Talks to the Oscar '13 Nominees: Jessica Chastain on the Obsessive Secrets of Her Role in 'Zero Dark Thirty'

So you didn’t have to audition for Kathryn? That's pretty astonishing, considering that last year was dubbed your 'Breakout Year.'

My movies have only been out for a year and a half!

What do you make of that trajectory?

It feels overnight, doesn’t it? But I’ve wanted to be an actor for so long. I’m not 17 years old. I didn’t take the quick path, so it doesn’t feel overnight to me. The very strange way that my life has changed is that I get a call from Kathryn Bigelow on my cell phone. The idea of that happening two years ago, I would’ve never imagined. That’s how my life has changed, and that’s all for the better. But I’ve worked really, really hard.

Someone said to me -- we were talking about luck in the business, and, yes, luck has a lot to do with it -- but I had a great teacher that said: “Success is when luck meets preparation.” I believe that everyone gets lucky at some point; you just don’t know when it’s going to happen. Melissa Leo got lucky. It probably happened later than she thought it would. Mark Ruffalo did; he was bartending for 19 years before he was discovered. You just have to be prepared when your luck meets you. And that’s how I’ve always been; I’ve always been a workhorse. I love being an actor. No matter what I’m working on, whether it’s a play or a guest spot on a television show, I give it my all. I think, because of that, when certain things would happen and I’d get lucky, I was prepared. I was ready for it.

Does getting a call from Kathryn Bigelow and getting an Academy Award nomination make you supremely confident about your craft, or do you still have insecurities?

I think if I ever start to feel really confident about my craft, then I might need to be doing something else. For me, being an actor is about overcoming something. It’s about going beyond what you thought you could do. When I look at people like Isabelle Huppert, who is a great role model for me, her career – she’s constantly challenging herself, and doing theater. She puts herself in situations where: okay, we all know she’s a genius and a brilliant actress, she could take the easy road right now. But she doesn’t. She’s always putting herself in a situation where she goes: “I’ve never done this before. Let’s see what happens.” And that’s what I really respect. So if I ever start to feel like “Oh, I know what I’m doing, I’ve got this,” I’m probably not doing what I should be doing.

How much did this role scare you, in particular? It's no doubt a daunting task to embody this woman.

Every possible way, this role scared me. I’ve never carried a film like this. I was in a movie called “Jolene,” but I’ve never done anything like this. This is a major motion picture, a lot of attention, Kathryn Bigelow, a very large budget, I’m playing a real woman in a very important historical event -- there’s no room to fail. I can’t just show up and go, “Okay, I’ll just play myself as a CIA agent.” That’s not what I’m doing. So, yes, every part of it scared me. It scared me to think that I was going to be away from my friends and family for four months. The idea of all the research I was going to be doing for this film scared me. I wasn’t interested in reading about Osama bin Laden. But when I got the part, I realized that I needed to learn everything I could. I had to get interested right now. There’s a book called "The Looming Towers," which is a brilliant book. So it was daunting on all sides, but just like everything I do, I try to make it.