Blond, blue-eyed Miller has ramped up her career since the birth of her daughter in 2012.

Next month, she takes over as singer Sally Bowles for the final weeks of "Cabaret" on Broadway.

The musical set in pre-World War Two Berlin is a world away from her role in "American Sniper" as Taya Kyle, whose husband Chris, played by Bradley Cooper, was the deadliest marksman in Navy history.

The Clint Eastwood film opens in US theatres on Friday and depicts the impact of war on a soldier and his family. Kyle survived four tours in Iraq but was killed by a disgruntled US veteran at a gun range near his Texas home in 2013.

Miller, 33, spoke about film choices, motherhood and playing real people.

Q: What attracted you to playing Taya?

A: The story was so interesting to me. It is so culturally far removed from where I've grown up and the world I have lived in. It is undeniably compelling and the idea, as a new mother, of being in that position of having children and not knowing every day whether your husband would survive, and what that would be like.

Q: Has motherhood changed your career choices?

A: I felt for awhile that I had done work that I was proud of in films before and then been maybe disappointed with the ultimate result. I knew what I was capable of and I knew what I was exploring, but I never had the experience of working with the best directors. And somehow having a baby changed things.

Q: You've recently played American characters. Why did you go after those roles?

A: It's more interesting to me to explore something that is far away from what I am. Bradley and I went on to do another film after "American Sniper" and I play someone English and I sound like myself and I just felt so self conscious through the whole process.

Q: How intimidating was it playing Taya?

A: In playing a real person you want to do your best to capture as much as possible of their energy and spirit ... You just try to capture the essence of someone and then lean on Clint Eastwood.