Bale and Wahlberg Dish on Making "The Fighter"

"The Fighter" stars Christian Bale and Mark Wahlberg get into the ring with "Extra's" Mario Lopez to talk about making their gritty boxing film.

Based on the life of pro boxer "Irish" Mickey Ward, Wahlberg said the film took nearly five years to make. "I made a promise and commitment to Mickey, and I was willing to fight to get it done," the actor explained.

Bale plays Ward's wayward brother and trainer, a role for which the actor lost weight. "It's no easier for me than anybody else. I'm starving, I'm hungry as hell. But there's nothing like boxing to get you into shape and drop pounds."

When asked what the most important ingredient to his success, Wahlberg elaborated, "The fact that former underwear model/white rapper was able to create the career that I have. I was being frowned upon, I was being laughed at, but I didn't mind, it was all about putting in the work."

Watch more of the interviews, plus find out how Wahlberg got his daughter to meet Justin Bieber!

"The Fighter" punches into theaters Dec. 10.