Mark Wahlberg, Christian Bale and David O. Russell aren’t men who shy away from a fight. Each has a haunting tale from the past where their dark side got the best of them; whether it’s Wahlberg’s early prison stint on assault charges, Bale’s notorious on-set rant or Russell attempting to choke out George Clooney while filming Three Kings. But when the three men bound into a press conference to promote their new film, The Fighter, it’s all jokes and hugs and laughs. This time, it seems, all the drama stayed on the screen.

The Fighter is the true story of boxer “Irish” Micky Ward (Wahlberg) and his crack-addicted older brother and trainer, Dick “Dickie” Eklund (Bale). It’s a film Wahlberg championed for four years, eventually signing on as a producer, and one that will almost surely land Bale an Oscar nomination for his portrayal of Micky’s squirrelly, charismatic, troubled but loving other half.

Asked how he got into the role, which required he drop down to an almost Machinist level of emaciation, Bale grins. “I felt so good and calm playing Dickie. I was just running. I could run for hours. Usually I say, ‘Oh, I just did a lot of coke,’ when I lose weight for a movie, but I don’t think it’s so funny for this movie,” he says, causing the entire room to erupt with laughter.

For Wahlberg, he explains he signed on to star and produce the project “out of sheer desperation to get the movie made. It seemed, at first, like a no-brainer,” Wahlberg shrugs, “amazing parts, wonderful story, a new and interesting world you’re not that familiar with, but it just wasn’t meant to be.”

After losing both Matt Damon and Brad Pitt, who would have played Bale’s role, and director Darren Aronofsky, who eventually signed on as a producer instead, Wahlberg says he “had to grab a hold of [the film] and force it to happen out of sheer will and determination.” Though, when it came to casting Bale, the inspiration came in the least likely of places.

“These guys met at preschool, right?” director Russell asks his two leads.

“Yeah, dropping off my daughter,” Bale grins.

“[Mark] looked across the parking lot, saw Christian Bale and was like, ‘BING!’” Russell laughs.

“What I said was, ‘There is the guy who’s not scared of this part,’” Wahlberg corrects. “Everybody loved the idea of [playing a drug addict] but nobody wanted to commit and go there. I’d seen The Machinist. I’d seen Rescue Dawn; he’s a fearless actor. He responded to it immediately, and everything fell into place after that.”

When asked about bringing in Russell, whom Wahlberg previously worked with on Three Kings and I Heart Huckabees, to direct, Wahlberg has a moment of quiet sincerity, “That’s my brother, man. We’ve been through a lot together, and we’re so comfortable with one another. We’re like family. To be able to work with someone you admire so much, and you trust and care for, I just loved it. When it dawned on me that there is a way to get this movie made with David as the director, I thought we have a chance to make something really special. He brought a level of humor and emotion that I don’t think anyone else could have brought.”

“A lot of other people were overemphasizing the druggy nature, the addiction, as if that was something fascinating to see,” Bale adds. “We both felt, we’ve seen that in so many movies, and [when you] meet Dickie and Micky, it’s not what you think about.”

More importantly, Bale felt it was the director’s emotional nature that made him the perfect choice.

“David’s got this great earnestness and complete silliness at the same time, which was perfect,” Bale says. “He’s got a big heart. He’d often be crying with laughter and also just flat out crying. [He’d be] listening to Dickie or Micky, and they had his sides splitting with laughter and then it would segue into tragedy, and he’d be bawling his eyes out. You could really see how much he felt it and was going through a roller coaster of emotions, which is usually what the actors are doing, but David was right there, feeling it as much as any of us.”

The Fighter releases in select theaters Dec. 10.