A Motion Picture Perfect Match

Actor Viggo Mortensen has a history of selecting violent roles for his movies.

Perhaps best known for his portrayal of the warrior king Aragorn in the "Lord of the Rings" trilogy and Tom Stall in "A History of Violence," Mortensen is now appearing as Russian mobster Nikolai Luzhin in "Eastern Promises."

He is joining forces again with "A History of Violence" director David Cronenberg for this new movie, which came in at No. 5 in the box office in its nationwide release this weekend. It also won the Toronto International Film Festival's Cadillac People's Choice Award earlier this month.

Mortensen and Cronenberg joined Rolling Stone's Peter Travers on ABC News Now's "Popcorn" to discuss their most recent project.

Working Together

The director and actor have nothing but praise for each other.

Cronenberg is especially proud of the way the partnership turned out this time around.

"I'm very satisfied with the movie and there are so many surprises that happened as we were shooting it, because of the collaboration I had with Viggo," he said.

Mortensen defended the director who has been criticized for the violence in his movies. "Some people say, 'I'm put off by the way [the violence is] so in your face, he seems to be getting off on doing that as a director,' and I feel that the opposite is true," Mortensen said of Cronenberg.

"I think he has more integrity than most directors and is more honest about showing violence because you take it seriously, you say, 'This is what [violence] really looks like,' Mortensen added. "It's not cameras doing this or that ... and that makes [him] more responsible than most directors."

The Notorious Bath House Scene

One of those surprises Cronenberg mentioned may have been Mortensen's decision to film a fight scene in the nude.

"[The scene] was in the script, but [the writer] never talked about nakedness. He just said Nikolai is sitting there in the steam and two guys walk in and pull out their knives and then there's a fight. He never says the towel falls down or there is a towel or not, so if you read the script it wouldn't hit you that 'Oh, yeah, this guy is probably going to be naked,'" Cronenberg said of the scene. "Once we did the choreography ... Viggo just said, 'Well, it's obvious I'm just going to have to do this naked.'"

Mortensen says the filming the scene in the nude made it more realistic, but it did present some complications.

"The only dangerous part is you have actors doing their own stunts. One of them is naked and therefore can't wear padding. And he's getting bruised and the makeup guy is saying, 'I'm spending more time covering up Viggo's bruises than I am putting on tattoos,' and I say, 'I don't even want to hear that,'" Cronenberg said.

More Than Decoration

The tattoos were meant to stand for something much more than decoration.

Cronenberg said the tattoos represent a criminal's entire life.

"[There is] a subculture of tattooing in Russian prisons, whereby the tattoos would represent your whole life, they were like your passport," he said. "[The tattoos say] what crimes you've committed, where you've done time, what prisons, how long, what your sexual orientation is, where you are in the hierarchy of the mob structure and so on."

The tattoos that are on display in the naked bathhouse fight were Mortensen's idea, according to the director.

"[It's] really Viggo's fault that [the tattoos are] in the movie. He did some research and ... Viggo found a book called 'Russian Criminal Tattoos' which had photographs of prisoners with their tattoos and then the meaning of the tattoos," Cronenberg said.

So how long did it take to apply the tattoos on Mortensen each time?

"The first time it took longer because [of] trying to figure out exactly where they're placed," Mortensen said. "The religious imagery is just code for something else that has to do with criminal activity or standing, but if you change the placement on the body, it means something slightly different, so we had to play around ... it took a few hours at least."

For the full interview with David Cronenberg and Viggo Mortensen tune in to "Popcorn," which airs exclusively on ABC News Now. "Eastern Promises" is currently playing in theaters nationwide.