The film role Christian Bale wouldn't gain weight for

Actor Christian Bale put his foot down over a new movie role. Photo / Getty

Christian Bale's responsibilities as a father prompted him to rethink his role in Michael Mann's Enzo Ferrari biopic.

The Dark Knight star was cast as the legendary Italian car manufacturer and racing driver last year, but the part required Bale to pack on the pounds to accurately portray him.

The British actor has previously tested his health for roles by losing and/or gaining weight for The Fighter, The Machinist and American Hustle, but this time, he decided it was too much and walked away from the project in January.

Bale has opened up about his concerns, admitting his advancing age means his body can no longer tolerate drastic changes to his waistline.

"I'm just getting older," the 42-year-old told The Associated Press. "I could lose and gain so much weight before and didn't feel any different. I just felt invincible."

It's not just the weight gain which worried the father-of-two: "I've had a series of accidents - motorcycle accidents, concussions," he explained. "I've got so much metal in my body holding me together.

"It's a great shame because Michael is a very good friend and it was a very special thing, but I just had too many red flags. And I'm a dad. I'm not f***ing around with that. So I just said I've got to surrender on this one."

Director Mann has yet to announce a replacement for the biopic. Meanwhile, it wasn't the only movie Bale wanted to drop from his work schedule; he has also confessed to almost walking off the Las Vegas set of Terrence Malick's new romantic drama, Knight of Cups.

The filmmaker, who also directed the actor in 2005's The New World, is known for his unconventional approach to moviemaking, but his penchant for developing the script as the cameras rolled nearly caused Bale to quit as he was simply exhausted after a long night shoot.

"So this one morning, I went, 'That's it. I'm done. I've got no interest. I don't really care. I don't want to make this anymore. I'm done. I've got nothing.' And (Terrence) went, 'Start filming immediately, this is fantastic.' Because it's sincere. I'm always an actor who wants to quit acting and he just went, 'Great'."

- AAP