Christian Bale's gaunt appearance in the 2004 psychological thriller The Machinist shocked audiences who were used to seeing the star's normally athletic figure onscreen—and now it has been revealed his drastic physical transformation wasn't originally in the film's script.

In a recent interview, Christian's co-star Michael Ironside said the actor's radical 60-pound weight loss was the result of a simple typo.

"The writer is only about five-foot-six, and he put his own weights in," he said. "And then Chris did the film and Chris said, ‘No, don’t change the weights. I want to see if I make them.' … So those weights he writes on the bathroom wall in the film are his actual weights in the film.”

christian bale, the machinist

(Photo Credit: R/R)

Michael also said the role of Trevor Reznik was meant for a much shorter actor, but once The Dark Knight star was cast, he was adamant about making the specified weight for the character.

Soon after reaching 121 pounds for the role, the 6-foot actor reportedly began gorging on pizza and ice cream to bulk up over just six weeks to play the title character in 2005's Batman Begins.

"I overdid it because I was enjoying gorging. I was ignoring advice about taking it slowly because my stomach had shrunk, and I should just go with soups. I was straight into pizza and ice-cream and eating five meals in a sitting. My stomach expanded really quickly. I got very sick during that time, but I enjoyed getting sick. I didn't mind it at all," Christian previously said of his yo-yo dieting.

Watch the full video of Michael's interview with HuffPost Live here.