Though he has one of the most varied resumes of any actor of his generation, Liev Schreiber knows that the public thinks of him only in terms of certain roles. He's the star of urbane indies like "Walking and Talking" and "The Daytrippers." He's the Tony-winning Broadway thespian from "Glengarry Glen Ross." He's the erudite voice of countless big and small screen documentaries.

So Schreiber wasn't surprised that fans were initially skeptical when he was cast as the powerful and vicious Victor Creed, whose Sabretooth serves as the main nemesis opposite Hugh Jackman in this summer's "X-Men Origins: Wolverine."

"I felt very self-conscious initially because I knew fans didn't like that idea of me playing Sabertooth. I think I am perceived as a kind of urbane New York.. I don't know maybe I've done too many movies with Jewish characters and they're like 'It's like Woody Allen playing Sabertooth.'" Schreiber chuckles. "And I'm like no actually it's not. I'm 6'3." I'm bigger than Hugh Jackman. I can do this."

Indeed, it isn't like Schreiber has only taken roles that would allow him to spend January at the Sundance Film Festival. From John Clark in "The Sum of All Fears" to Raymond Shaw in the "Manchurian Candidate" remake, Schreiber is no stranger to physical parts. He may have cut his directing teeth on the intellectual "Everything Is Illuminated," but he'll next be seen as a butt-kicking Jewish resistance fighter in the late-December release "Defiance." And, as he says, he's every bit Jackman's physical equal.

"I can take him," Schreiber tells a room of "Defiance" junketeers, pausing for laughter. He takes a beat. "No I really can. In fact I do. But the reality is that he's become -- Hugh since I've known him, I've known him a long time -- has become this colossus of a man. He's huge and muscles everywhere and I have to play this guy who whoops his ass. So as soon as I was finished 'Defiance' I began this kind of four month training period, weight lifting period genocide of chickens phase of my life where I just got bigger and bigger and it was awful but amazing and fun. When I finally got there and I got to choreograph the fights with Hugh and get on the wire and do the work it was not just fun, I saw some footage it's pretty cool."

Schreiber's commitment to playing the impossibly strong Sabretooth went beyond the weight room, though. Intellectually, he compares the process to the one he undertook on "Defiance" to play Zus Bielski, the most volatile of three brothers (along with Jamie Bell and Daniel Craig) holding out against the Nazis in the woods of Belorussia.

"I read the comics before I got offered the part. I mean I knew the character really well," Schreiber says. "Initially I was asked to play Stryker [Danny Huston in the movie] and I asked 'Is there any chance I might be able to play this Victor Creed guy?' The research that I did on it, Victor's particular mutant issue has nothing to do with his name Sabertooth, but that was the place I decided to start. Just what is a Sabertooth and how does that work? How do they move? What are their behavioral characteristics? I knew this stuff from the comic, I knew that he was just a complete savage street fighter and that was his MO but what I hadn't seen in some of the earlier films that I was curious to kind of pursue is what drives the guy and what are the kind of qualities -- I guess for be it's the same thing with a character like Zus -- rather than just say they're a violent brute what's the cocktail that makes the brute tick. Hopefully people will like it."

And while Schreiber might love reading Mamet or narrating a Nova special or two, he isn't shy to admit the pleasure he gets from firing a World War II machine gun or brawling with The Sexiest Man in the World.

"Ever play cops-and-robbers or cowboys-and-Indians? I hate if I'm blowing anyone's cover here. I don't think men really grow past 22 intellectually," Schreiber explains. "Do you know what I mean? Physically we just grow older and we are less capable of doing the things we want to do but I don't think we stop wanting to do them."

"Defiance" opens limited on Dec. 31 and goes wide on January 16.

"X-Men Origins: Wolverine" opens on May 1, 2009.