She has no character name and no dialog, but the actress Lucy Walters creates an indelible impression in Steve McQueen’s “Shame” as the Manhattan subway commuter transfixed by a handsome male passenger’s coolly libidinous gaze. Such is her arousal, that wedding band she’s wearing looks like it would come off as easily as anything else she’s wearing were she and her admirer, Brandon (Michael Fassbender), likely to find themselves alone. The woman doesn’t know, of course, that he’s a self-flagellating sex addict, but one rather suspects she would be more intrigued than deterred by his neurosis.

Walters studied at the University of Texas at Austin before moving to New York five years ago. Since then the Brooklyn resident has demonstrated her natural comic flair in a couple of shorts and appeared in “Gossip Girl,” “Army Wives,” and the upcoming movies “The Brass Teapot” and “Bastards of Young.” In the following interview she indicates the level of intensity serious actors bring to the tiniest parts to make them believable. Very soon, Walters' roles are certain to get a whole lot bigger. As “Shame” recognizes, she’s one to watch.

ARTINFO: How did you get the part in “Shame?’

LUCY WALTERS: It was all down to [casting director] Avy Kaufman. She auditioned me for one of the girls Brandon talks to in the bar. I wasn’t right for that, but she liked something about it and set up a meeting for me with Steve and Michael on the set at 11 one night. I talked to Steve in Michael’s trailer, then had a get-to-know-you session with Michael. It was nothing business or craft-related. We just talked about our families and so on. It was a nice audition because it wasn’t stressed like most auditions, where all the focus is on you. They had bigger things to deal with. The machine, which was way bigger than I was, was already running, and they said, “Just from talking to you, it feels right. Your skin is translucent enough we’ll be able to read whatever emotions are on your face.” The trust was already there.

ARTINFO: Did you rehearse?

WALTERS: A little. But it was hard because they had so many scenes to get through on the subway and there were thousands of extras to coordinate. Stcve just said, “This is the arc I’d like your character to have, this is the journey that she takes.”

ARTINFO: There’s extraordinary erotic tension in your first scene with Michael Fassbender.

WALTERS: If it works, it’s all to Michael’s credit. He had such focus and calm about him, and that focus was contagious. He would say just enough to make me feel confident and beautiful and in a good place to work. If I lost part of what I was doing, I’d just lock eyes with him and that was enough to feed me. Of course, he was being incredibly sexy and it’s a very charged scene, which helps, but it was enough that he was being a generous actor.

ARTINFO: Did you create a back story for your character?

WALTERS: When I got the part I didn’t understand it. I was thrilled to get it and be a part of the film, but I thought I was pretty much a glorified extra and there didn’t seem to be much to it. But what became exciting about it was that, while there are moments in the film that are concrete, there are clearly others where people can project what they want on to them—which everyone I’ve spoken to about the film has—and this was one of those moments. So, yes, I did come up with my own story. I like to think Michael’s character and mine would see each other regularly because we have the same commute to work, though we don’t know each other. So there is a little bit of a shared history between these two strangers. But I see her as a newlywed, and while there’s clearly an excitement she feels from this shared thing with this man, which seems even more special because it’s serendipitous, it’s a little too scary because she has her own life and he has no part in it.

ARTINFO:  Your character very noticeably crosses her legs, consciously or unconsciously, for his benefit. Was that your idea?

WALTERS: I think that was a fluke of rehearsal. My memory is that I did it and Steve said, “Keep it.” I’m possibly being a revisionist historian here and it was Steve who came up with it and now I’m taking credit for it, but however it happened he knew it was a keeper.

ARTINFO: What is she thinking and feeling the second time he sees her in the film?

WALTERS: I know it’s Brandon’s journey, but in that time she’s had her journey, too, and maybe by then her real relationship isn’t being all that she hoped it would be, so she finds herself much more excited by the possibility of what this stranger on the subway might represent for her and has become more open to it. Does something happen or not? We don’t know and I love the ambiguity of that. That kind of economic writing is very powerful to me.

ARTINFO: Do you think she’d sleep with him?

WALTERS: [laughs] I do, but not at the beginning. It’s a little crazy to think what a Lothario he could be without even trying, though maybe at the end he’s in a different place.

ARTINFO: Why did you want to become an actor?

WALTERS: I love telling stories. As I kid I used to do the children’s parts in the Houston Grand Opera and I grew up as a violinist so performing was very much part of my upbringing. The natural progression was to musical theater, but I thought, “I’m not that breed.” I studied theater in college, but more as a cross-training for my brain. It wasn’t until I moved to New York and started seeing good plays and films that I started to realize how powerful they could be. Sometimes our awakening comes a little later than it should.

ARTINFO: What do you want from your career?

WALTERS: Everyone dreams of being in important films, by which I mean films that have weight, that mean something, not that I don’t love “silly,” too. When I have complicated feelings about being an actor, that’s when it’s about myself. When I feel at peace with my choice to pursue this crazy career, it’s because I know I’m involved with something that’s bigger than myself and I can just lose myself in it. As an actor, you’re the paint on an artist’s canvas.