Christian Bale keeps pulling a Bruce Wayne on the set of his new movie, frequently disappearing on set.

The actor has bemused co-stars on his new movie The Fighter, which he is filming in Massachusetts with Mark Wahlberg and Amy Adam, with his insistence on “getting into character” and refusing to be seen when he isn’t filming.

A source told E!: “You only see him when it’s time for his scenes. Other than that, no one has any idea where he is. He just goes missing.”

Bale is determined to accurately portray former crack addict Dicky Eklund in the movie, which follows the life of boxer “Irish” Mickey Ward, and has stunned people with his appearance.

The source explained: “Christian has lost almost as much weight as he did for The Machinist. He is so gaunt. They have even thinned his hair—he just looks sickly.”

The 35-year-old star famously lived on just a can of tuna and an apple a day and lost 60 lbs. while filming The Machinist, in which he played a paranoid insomniac. Bale has previously said he would not want to go to the dieting extremes he did for The Machinist ever again, but admitted he thrived on the “mental challenges” it presented him with.

He said: “I wouldn’t want to take it to that extreme again. But it was necessary to lose weight for that role—not as much as I did—but it was a challenge mentally to see if I was capable of doing such a thing. I know that I can now, so there would need to be a certain gimmick if I was to do that all over again. But I do like the notion of seeing how far you can push yourself so I’m very happy that I did that. Everybody told me that I was risking my health the first time around, so doing it twice? I’m probably being an idiot.”