Viggo Mortensen may have galloped his way into our collective pop-culture consciousness as Aragorn in The Lord of the Rings, but he was already mesmerizing a full decade earlier in Sean Penn's The Indian Runner. His post-Rings output has seen some similarly impressive portrayals, particularly as the suburban-dad-with-a-past in A History of Violence and the coiled-spring Russian mobster in Eastern Promises. His latest role, in The Road, which opens today, is similarly affecting. Based on the Pulitzer Prize-winning Cormac McCarthy novel, the film follows a man and his son as they navigate the scorched landscape of a post-apocalyptic earth, with Mortensen playing the physically and emotionally emaciated father. The actor was kind enough to sit down and talk to us about his latest work, the emotional impact it had on him, and (couldn't resist!) whether or not he'd be up for appearing in The Hobbit.

You've been doing a lot of publicity for this movie...

Three months straight. I've done a lot because this movie needs awareness. Especially in a season where all kinds of movies come out and people invest in a lot of TV ads and all that. You need to get the word out for this kind of movie. It sounds really dark, but once you see it and realize there's something uplifting about it, it's worth going on that tough journey...I feel good about it creatively, I know that it's a very faithful adaptation of a beautiful book, a beautiful story, and I know it's a movie that will be seen and have a special place for years to come. But I want people to come see it in the movie theaters.

There's the stigma of the movie's release being held back so often.

Almost always that means you see it and go, "Oh, I can see why they didn't release it," but not this. It makes some sense to me that they held it back. It's an autumn, a winter kind of story. I'm an optimist. I've done so many Q&As, I've never done so many, and the way the audience reacts, the things they say afterward, it affects them personally. And it's not like crying a little, it's a profound effect. It really makes you think about family and the brevity of life. I love that line toward the end where the father finds acceptance, with the voiceover straight out of the book: "If I were God I would make the world just as it were, no different." It's simple, but profound. That's the first step no matter what your situation is in life, how bad it is. The first thing you do is accept it. It's not ever over 'til it's over.

[Director] John Hillcoat told me that Cormac McCarthy stopped by the set with his son. What was that like?

You could see where the story came from, with their interaction. It's always nice when an important, Pulitzer Prize-winning novelist comes by the set and says he liked it. Did John tell you the story of when Cormac saw the movie? They flew out to Santa Fe and screened it for him to get a reaction. Blessings, changes, you know.... At the end of the movie, he gets up without saying a word and leaves. Everyone looks at each other, thinking they're screwed and he hated it. He's gone only ten minutes or so but to them it seems like forever. And when he finally does come back, he sits down, and says "I'm sorry, I had to go to the bathroom. But it's good. It's really good." Everyone was so relieved. Certain writers who get their books made into movies just come out to harass the set, but he seemed very proud.

Did you read the book before you saw the script?

No, but I had read all of his other books. I have particularly always liked his descriptions of landscapes. Blood Meridian is horrifying, with its descriptions of that border landscape. And its inner, dark themes are like the burdens my character was carrying. That's why people said it would be hard to adapt this into a movie, but you can do it visually. It's in the interaction between the man and the boy. If you see that, feel that, on an emotional level, then we've matched the book, on our own terms, which I think we did.

You look so gaunt and hollowed-out in this movie. How did you prepare?

That was a surface thing but it's obviously necessary. I had to have a certain amount of self-discipline and lose a certain amount of weight. But mainly it was just making a leap of faith more than I've ever had to do. It was a culmination of a period of work over the past ten years of certain things I've done with characters, but never more so than here, where it was strictly an emotional challenge. I've done several movies where the environment was an important part, but in this case it was an emotional challenge that both attracted me and scared me. If I can have the guts to just go there somehow, it'll be worth it no matter what happens, no matter how the movie turns out. But I did need some help. I needed help from my acting partner. Before we started shooting I was wondering how we would be able to get a boy who could handle this material. Not just have some emotional range, but actually understand the story and deeply feel it. Once Kodi Smit-McPhee and I started working together, I liked him. We became close friends very quickly and I realized very early on that no matter where I went emotionally, putting myself out there, he was going to catch me. And I would catch him. The first week or so we shot some pretty emotional scenes and that really made us bond. He's such a beautiful boy with such a beautiful presence, and his heart and soul is in this movie. Our combined heart. It sounds really sappy but it's true. This movie wears its heart on its sleeve, and those two characters, the affection they feel, was real between me and Kodi, and you can really feel that on the screen. For me, that's always going to be a memory seared into my mind.

You have a son, yourself. Did you draw from your own experiences as a father?

My son is 21 and in his last year in college, but I remember him at that age. In the same way he had that wise, compassionate quality that the boy's character has. Yeah, I thought about that a lot, and talked to Cormac McCarthy about his son and my son before we started. But once I met Kodi, that was irrelevant. Even the blood tie was irrelevant.

Was there anything in the story that you found especially moving?

Ordinary people having to come up with extraordinary reactions to very difficult circumstances. Those are the kind of stories I liked to see as a kid, and I still like to see now as an adult and as a person in the movie business who watches it for craft and veracity. The story tells us that there is a nobility to just doing the right thing and being kind. Even if the circumstances tell you, "What's the point of being nice? Why be kind?" In itself, it's worthwhile. It's important to appreciate that. You take your TVs away and you take your houses away, take everything away, how do characters find hope where there is none? That's what attracted me to the story and that's what I like about the movie because that's what you're left feeling.

I have to ask you, would you be up for appearing in The Hobbit?

Well, I don't know anything. But, of course, it would be a really cool experience. There's 60 odd years between the [The Hobbit and The Lord of the Rings]. My character's alive at the time the book is set, he's just not in it. But a 60-year gap is nothing, just a year or two, for my character because he lives so long. I guess they could easily make a bridge to work if they wanted to, using Tolkien's appendices and whatever they have permission to use. Aragorn could easily be there, and you could have Arwen, you could have Legolas, you could have a lot of characters that people are familiar with. As long as you make The Hobbit with integrity you can make it. I mean, I don't even know if this is a consideration or if it's just rumors. I know what you know. Less, probably. But obviously if they said, "You wanna do that?" I'd jump at it. I'd love to go back to New Zealand and play the character. I still have the clothes, I still have the sword, and my hair is long. So I'm ready to do it.