His role as the fearless warrior Aragorn in the "Lord of the Rings" trilogy shot heartthrob Viggo Mortensen to international fame. But he'll trade the sword for the steering wheel in his latest film, the mafia drama "Eastern Promises."
Mortensen plays Russian-born Nikolai Luzhin, a driver for one of London's most notorious organized families.
"There was a lot I had to learn on this movie, speaking Russian, as we do in some of the scenes," Mortensen said today on "Good Morning America." "But I met some Russian people, including people that have pasts that are not unlike my character's. Once they realized I wasn't going to be making fun of them or judging them, they were really helpful."
Mortensen said he enjoyed working with his co-stars, including Naomi Watts.
"She does such fine work," he said. "It's great to work with someone who is so detailed and so subtle with their acting. It's really a nice dance that you have with a person like that who is that talented.
"But you need a director like David Cronenberg, who takes care of those little hesitations, those little smiles she gives," Mortensen continued. "A lot of directors would go, whatever, get on with it and it wouldn't be in the movie. But she [Watts] gives a very well-balanced performance and she's easy to look at."
In the movie Mortensen said his character has an "interesting relationship" with Watts' Anna Khitrova.
"She's an English midwife and I'm this Russian underworld type," he said. "At first there is the man-woman thing, but there is also a big cultural divide. She doesn't trust me. I don't know when she's making fun of me. Eventually they connect."
In the film, Mortensen sports several fake tattoos that took hours to apply each day. All are on display during the final scene, shot in a bathhouse.
Mortensen said it was only natural to perform the scene nude. "I don't think it's realistic that a towel would stay on the whole time," Mortensen said.
"Eastern Promises" opens in limited release Friday, Sept. 14, and nationwide Sept. 21.