With Lord of the Rings: Return of the King, the J.R.R. Tolkien trilogy is finally complete (and in case there's any doubt, the film bluntly states ''The End'' before the credits roll). But Viggo Mortensen, 45, isn't hanging up his saddle just yet. The artist-actor is riding his newfound fame into another equine epic, the real-life story of Pony Express carrier Frank T. Hopkins, in Hidalgo (opening March 5). Mortensen has also been crossing swords with pro-war advocates who see Lord of the Rings as a call to arms. And if Aragorn tells you to put down your weapons, you might want to listen.

The trilogy has been wrapped up. How does it feel to be done with it?

I'll let you know when I feel like it's over, because it doesn't feel like it's over yet at all. But maybe I'm sort of in denial.

Lord of the Rings propelled you from cult status to the A list. Have you gotten comfortable with fame?

I'm grateful that I have opportunities to do other things. I wouldn't have had a chance of even getting in the room to audition for Hidalgo, much less getting the role, until the success of Fellowship of the Ring. I sell a lot more books [he owns his own publishing company, Perceval Press], a lot more people come to my art shows, and if I put together an event with other poets people show up because of these movies. I realize that's what brings them there, but I think that's great. Because once they show up, it doesn't matter why they came.

C'mon, tell us: What's the secret to your success?

I have friends who are really good actors who don't come close to making a steady living, and I don't really understand it. You do have to be lucky. I certainly have always worked hard at every job I've had, but I don't have an easy explanation for why I got this part and not someone else. I don't feel guilty about it, but I think it's good to be conscious of the fact none of us are more gifted than others.

You were called in at the last minute to replace Stuart Townsend as Aragorn. Did you hesitate before taking the role?

I actually told my agent I didn't think it was a very good idea. I hadn't read that book, and at the time the rest of the cast had been in New Zealand rehearsing for a couple of months. I felt that I was at a disadvantage, and not just personally. You don't want to have a movie come out where people say, ''Everyone was into their characters except this one guy who didn't seem to know what story he was in.'' But I'm certainly glad I did it.

Even more than its predecessors, Return of the King tackles heavy issues like mortality, betrayal, and personal responsibility. Did this change you at all?

I'm wary of anyone who says, Hey, I just went to Thailand, I'm a new person! I think we are who we are. On the other hand, I would say I would be surprised if anyone involved in this project didn't say that it affected their lives in some way. For me it reinforced certain ideals that, at my best, I more or less adhered to before doing this movie.

What are those?

The idea of compassion. The idea that we have more in common with others than not, be they hobbit, Iraqi, Elf, French, Canadian, cows, horses, dogs, pigs, or sheep. As an individual, you're going to be stronger, smarter, more well-informed and more well-rounded if you consciously make an effort to connect with others. Joseph Campbell said all life is sorrowful and we can't change that, but we can change our attitude towards it.

How did you apply that theory to getting along with the same coworkers for four years?

You can be working with a group of people and get really annoyed. It could have gone that way for us on the trilogy. But everyone found a way to look past their different points of view about the world. We worked for each other and found that was the best way to work for ourselves. Whatever presented itself, there was an unspoken understanding that the others were there for you and you for them.

You've been outspoken in your disapproval of The Lord of the Rings being used as a metaphor for the U.S military involvement in Afghanistan and Iraq. Do you feel a responsibility to defend the film's purpose?

I don't feel obligated or on a mission or any of that. When I appeared on The Charlie Rose Show [last year], I was responding to certain comparisons being made that I found very faulty. If you want to compare these stories to the U.S. invasions of Afghanistan or Iraq, then don't get the comparisons quite so wrong. Tolkien himself was reluctant to allow others to compare his books to WWII and was very upset by Hitler incorrectly applying Nordic mythology to justify what the Third Reich was about. And I objected on some level to the same thing being done with The Lord of the Rings. I finally said, Enough. You realize by saying nothing you're tacitly agreeing. So I felt I had to say something about it.

On a lighter note, you took up surfing for the first time in New Zealand. How did that go?

Let's just say I'm not as good as the hobbits.