Christian Bale adopts a method acting approach because he ruins scenes by laughing if he knows his co-stars too well.
The 45-year-old actor is known for immersing himself into his characters and isolating himself away from the rest of the cast and he's admitted he had to take on the technique to stop himself from disrupting filming.
Speaking to MovieMaker.com about his role as Patrick Bateman in 'American Psycho', he explained: "I start laughing if I know people too well. I start laughing in the middle of scenes. Especially with a character like that."
Christian's co-star Chloe Sevigny was convinced his stand-offishness meant he didn't like her and she found shooting with him "pretty hard" so she was pleasantly surprised by how "nice" he was when they were promoting the film.
She said: "Working with Christian was pretty hard because I didn't know this whole Method thing. I was pretty fresh. I hadn't done that many films before, and that an actor would lose himself to such a degree and was so consumed by the part, I was having a hard time kind of... just wanting to socialise with him, but feeling that he didn't, and then my ego being like, 'Does he not like me? Does he think I'm a terrible actress?'...
"But then when we went to festivals and stuff after, like Berlin and whatnot, he was very friendly then. When we were not shooting, doing press and stuff, he couldn't have been a nicer guy."
And it took some time after making the movie for the Oscar-winning star to learn that the rest of the cast thought Christian was the "worst actor they'd ever seen" until they saw the finished film.
Christian laughed: "Josh Lucas and I did a film together recently and he opened my eyes to something that I had been unaware of. He informed me that all of the other actors thought that I was the worst actor they'd ever seen.
"He was telling me they kept looking at me and talking about me, saying, 'Why did Mary (Harron, director) fight for this guy? He's terrible.'
"And it wasn't until he saw the film that he changed his mind. And I was in the dark completely about that critique.