From director Jake Scott and screenwriter Brad Ingelsby, the indie drama American Woman tells the story of a single mother’s struggle to raise her young grandson when her teenage daughter mysteriously vanishes. When 31-year-old grocery clerk Deb Callahan (Sienna Miller) realizes that her daughter Bridget (Sky Ferreira) has gone missing, it turns her world upside down, and over a 10-year life journey of ups and downs, she builds a new life for herself only to finally be faced with the truth of her daughter’s disappearance.

At the film’s Los Angeles press day, Collider got the opportunity to sit down and chat 1-on-1 with actress Sienna Miller about how grateful she was to play a character with such depth and range, the experience she shared with the film’s director, playing a grandmother before the age of 40, the importance of the sister dynamic, and how much she enjoyed working with Christina Hendricks. She also talked about her incredible transformation to play Roger Ailes’ wife in the Showtime limited series The Loudest Voice, opposite Russell Crowe, the experience of wearing so much prosthetics, and why she thinks it’s an important story to tell, along with why she wanted to be a part of the upcoming film 21 Bridges, and following her intuition when it comes to reading scripts and pursuing projects.

american-woman-sienna-miller-interview
Image via Roadside Attractions

Collider: Really brilliant work in this.

SIENNA MILLER: Thank you.

It’s one of those things that seems like it must have been an intense nightmare while you were shooting it, but also rewarding, as an actor, when you finish it. Did it feel that way?

MILLER: You know, as you can imagine, it was a really hard thing to do, but I like hard work. I crave that. It was a relief to play somebody who was fully realized, and who begins as one woman and ends as another. It’s rare for women to have a role that has that depth and range, and I was just grateful for that opportunity.

And it’s such a long life journey of hers that we get to see too, in terms of years, which seems like something much more explored on TV than in film because there just isn’t the time.

MILLER: Yeah. This woman is knocked down so many times, and she gets back up. It felt really feminist. It really felt like a celebration of the resilience of women, and I know so many women who have that same strength. To see that in a film is rare, but it shouldn’t be. So, that was an exciting aspect.

Actors talk a lot about how they want to find roles that challenge and scare them, and this seems like it would be one of those roles. When you read this, what did you see as the challenges, and were there things that scared you about it?

MILLER: It’s funny, I read the script, and this happens rarely, but I had a total vision for her. I knew this woman. I knew exactly how to do it, and I was incredibly passionate about it. It was a very, very well written script, but I didn’t know if I wanted to put myself in the mind-set of confronting what it would be to lose a child. I was really on the fence for awhile, as far as whether or not I wanted to go through that. (Director) Jake Scott, when I met him, was just this loving and intuitive guy. In the wrong hands, this experience would have been torturous, but it was collaborative. I felt totally held, for lack of a better word, by my director. There are many directors out there that would’ve just tortured with it, but he didn’t. He was experiencing it, as I was. He was crying behind the monitor, when I had to cry. It was a very symbiotic, weird relationship that we had, but it was very, very close. I didn’t feel alone in it, but it was definitely hard.

american-woman-sienna-miller-interview
Image via Roadside Attractions

When you explore a topic like this, it seems like even if you try to convince yourself that you could keep yourself separate from that mentality, it would also be impossible to keep yourself separate from it.

MILLER: These things just seep in, by osmosis. It’s important, when making a film that deals with loss, that it’s not just about that, but the loss has to be somewhere close to the surface, at all times. My experience with people who have lost children is that it’s always just there. So, I had to keep it close, which was sad.

Could you ever have imagined that you’d be playing a grandmother, before the age of 40?

MILLER: I loved it. I’m up for anything. It didn’t even cross my mind. What makes me laugh is that Sky Ferreira still calls me mum, which is funny. She’s older than she plays. No, I loved it. Also, that exists. I’m kind of envious. I wish I’d had my daughter younger, and I could have grandchildren now. I’d like more children at my age now, too. There’s something to be said for that dynamic. I was 30 when I had [my daughter]. It’s a horrible facing of mortality. So, I’m all for young babies.

Was the woman that we see now the same woman that was on the page from day one? Were there things that got developed or added, or is what we see pretty much what you first read?

MILLER: It was really realized, more than you’d expect, or more than I’ve experienced before. The script had a lot of the character work built in, but of course, you add things as you go. You make it your own. With the young Deb, we improvised certain aspects of it and I beefed up the humor or the goofiness, like jumping up on counters. That wasn’t scripted. I had freedom to be noisy, and I felt like she should never stop moving, in that first chapter. And then, she gradually becomes still, by the end. I mapped out all of those things. I had to really work very hard because it was a small film and we shot it in 28 days. Sometimes I’d be Chapter 1 Deb, and then the next day, I’d be Chapter 3 Deb. We were moving around, with no chronological filming. It just took a lot of research and a lot of work. I had different colored post-it notes on different days, and I had color association for the Deb that I was gonna be. It’s a labor of love, doing a little film like this, and it feels like a big movie, in some ways, to me.

american-woman-sienna-miller-interview
Image via Roadside Attractions

I love the relationships between the women in this, whether it’s between mother and daughter, or between these sisters. Was that also a big part of the appeal?

MILLER: I grew up with a sister and a mother. That was my family, and I’m sure that resonated with me, on some level. I’m sure that was part of the appeal. That world was familiar. And I was probably the more reckless of the sisters. What I loved about this was that, without anything being hammered over the head, they’re in conflict a lot of the time, but there is this love that you feel between these two women. Really, the beating heart of the film is that sibling relationship. Having a sister who I feel like I share a heart with is something that I haven’t seen that often in film. I’m sure that was a really huge pull.

Because of the importance of that relationship, was it a bit nerve-wracking, waiting to find out who would be cast?

MILLER: It was essential, but that really comes from the director. He’s intuitive, and he cast it right. When I heard that Christina [Hendricks] was gonna play my sister, I said, “We just don’t look like sisters. How is that gonna work?” But then, she turned up, and we were sisters. I bought it completely. It was brilliantly cast, but Carmen Cuba is a brilliant casting director. We were fortunate because often that doesn’t happen, and you just have to act and get away with it. But when you feel the authenticity of a genuine connection, it definitely resonates with an audience more.

What was it like to take on playing Roger Ailes’ wife for Showtime’s The Loudest Voice? Is it fun to do something so transformative?

american-woman-sienna-miller-interview
Image via Roadside Attractions

MILLER: It was really fun. It was very, very liberating, and also really arduous to sit in a make-up chair for four hours, every day, sometimes for just walking into a room. You could have an eighth of a page to shoot, and you’d be in the chair for four hours. But I just feel like that’s a story that I wanted to look at right now – the inception of Fox News, how that came to be, and the affect that it’s having now. To be a part of that story is riveting and fascinating. I love prosthetics. I loved having that mask and the freedom that it allows you. You’re just not yourself.

What’s it like to actually look at yourself in a mirror and see someone who looks so different?

MILLER: For the first two weeks, I couldn’t look because I was just howling with laughter. The prosthetic was so seamless. My child was like, “Mommy, you look awful!,” when we were on FaceTime. But then, I got really used to it. The crew never really met me. Acting, as an experience, makes you go, “What’s it like to be this person or that person?” But to really be somebody else, and for people to not know you as anything other than that person, how people respond to you and react to you is fascinating.

Was it also odd to have the experience of looking at Russell Crowe, also being so completely transformed?

MILLER: Yeah, he really transformed. He’s phenomenal in this. We’d be in make-up together. We’d see each other at five in the morning, and he’d bring coffees in. And then, at the end of the day, we’d take our faces off and chuck bits of prosthetics at each other. We’d lob bits of meat at each other, and I got hit in the face with his chin once. It was pretty funny. I have videos of him removing his, and of flapping my neck at him. We just went for it.

american-woman-sienna-miller-interview
Image via Roadside Attractions

When you do stuff like that, does it make you want to do it again, or are you okay with not wearing prosthetics again for awhile?

MILLER: Yeah, I need a break from the time that it takes. It’s funny, in the last week, we got it down to two hours, but that was the last week of a five-month shoot. I’m really interested in the idea of using it to transform. People have preconceptions of who you are, and sometimes that’s hard to overcome. Sometimes it takes changing yourself physically for people to believe something. I would explore it more, but I definitely need a break. I’m good to wait for another year before I wear anymore prosthetics.

The woman that you’re playing in 21 Bridges also seems like a very different role.

MILLER: Yeah, she’s a narc detective. That was exciting, and very cool. It’s a very old-school cop movie. I don’t think they make movies like that anymore. It’s a Sidney Lumet type of movie. The director (Brian Kirk) did a fantastic job, and I’m just a huge Chadwick Boseman fan. That cop world is really, really intriguing. It’s corrupt and complicated, and the movie really doesn’t shy away from any of the complications of life. I think it’s gonna be good. It’s coming out at the end of September.

What is it that gets you excited about a project? When you read projects, can you pretty easily tell whether something is right for you or not? 

MILLER: Yeah, I have a pretty intuitive reaction to scripts. I know it’s something that I’m desperate to do when I have a vision of how to do it, instantaneously. Sometimes I get offered things and I feel like I could do it standing on my head, and I have to be careful of that because, if I get lazy, it’s not so good. And then, of course, there are things that I read that I love, but it doesn’t feel right. There’s not much more to it than that for me.

american-woman-sienna-miller-interview
Image via Roadside Attractions

How hard are the times when you deeply connect with something and you want it so much, but then it doesn’t work out?

MILLER: That’s hard because, if you fall in love with a story or a part and you have a vision of how to do it, often numbers play into it. Does this person have the bank-ability? I’ve had that before, where a director says, “You’re the person I want. I just can’t get the financing with you,” and maybe it’s because I don’t have huge box office numbers. I’ve always felt that, if you make a great movie, people will see it. You can have the two most bank-able people in the world in a movie that tanks. That kind of number crunching that goes on is a flawed system. I think people should focus on the script and casting, and make the best movie. That will get through.

After the experience you had on the Roger Ailes mini-series, has it made you want to do more long-form stuff to get to explore a character for a bit longer?

MILLER: I like the idea of limited series. I can’t imagine playing the same person for seven years. I love watching those shows, and I think they’re epic, but I would go mad. I’m too restless to stay with something. Maybe when I’m in my 50s, I could see how that would be a great thing to explore, to spend time with a character and age with it, and go on a journey. But right now, I just want a variety of experiences.

American Woman is in theaters now.