WSJ: You first played Nixon when "Frost/Nixon" opened in London in August 2006 and reprised the role on Broadway and for the film in 2007. Was it hard letting go of the character?

Mr. Langella: No -- I liked Richard Nixon and I liked playing him. I don't think he'll ever be gone from me, because something about the man is just very powerful. His pain, and the obviousness of his pain, stays with you. It's not a sentiment that's new to any of us -- you could see it on him at all times, his discomfort in public -- but I discovered he could be equally funny and charming. He just wasn't a relaxed man, and was forever churning away, trying to achieve greatness. But I'm deeply involved with playing Sir Thomas More now. Once something's over, you hang up the suit and move on.

Given his discomfort, he would not have done well in today's 24/7 news cycle.

Yes, there was at that point a certain amount of distance between the public and press but now, the ubiquitousness of the president, of all politicians, is remarkable to me -- they turn up on every show; I don't know how they have lives of any kind. The business of getting work done must be very difficult. Nixon wasn't required to appear that often.

Where were you when Nixon resigned in 1974?

I was in a theater rehearsal in Williamstown, Mass., working on a play. I was sitting on the floor of a little rented house with a script in my lap and I stopped and watched the resignation and then went back to work.

In plays, actors seem to derive their emotions from the momentum of a extended live performance. How do you recapture that for film?

You do what's required. If you're doing a play, you're not really doing a man's life, you're doing a microcosm of it. It's live and over in an hour and half. If you're doing a movie, and you're on a set for 18 hours a day for 35 days, and a makeup chair for two hours every day before you even walk on set, there's some little heartbeat that's going on all the time, that then has to really pump when you hear the word action. Between scenes, you just have to be a professional and maintain it -- but not to the point of any self-flagellation.

Much of the film was shot on location, including Nixon's beachfront property at Casa Pacifica in San Clemente and the home in Monarch Bay where the interviews were shot, which must have been energizing as an actor.

Absolutely, everything helps. Plus, all the interviews were shot chronologically, which was a smart idea on Ron's part, so the David-and-Goliath trajectory [Frost seen as a lightweight, Nixon the senior statesman] for Michael and I kept growing until we shot the final scene. [At right, a scene from the film.]

At various points in the film's development, it was rumored that Warren Beatty and Jack Nicholson would get the role of Nixon. How confident were you about eventually reprising your role for film?

I never thought about it specifically one way or another. Once the role was offered to me, after we opened on Broadway, I knew the role was mine. But until that point, I knew it was up for grabs. When I was in London, I had one phone conversation with Ron where I told him it was probably pretty obvious to him that I'd love to do the movie, and he said, just keep doing what you're doing, and I did. Worked out pretty well.