Keira Knightley will take a "long time" to stop seeing Sam Worthington as "arrogant".

The British actress appeared alongside the 35-year-old hunk in movie 'Last Night', and because of his decision to approach the role - about a husband and wife who have become complacent in their marriage - in a method style, he irritated both his co-star and the director Massy Tadjedin.

He said: "For the first week of rehearsals I got to know her, we had a barbecue and stuff, but I was struggling to get into the role. I thought if I treat her with complacency - like the characters in the movie - that might help. So in the second week, I became complacent.

"Actually, I was a bit of a jerk. I didn't turn up to rehearsals. Why? I couldn't be bothered. And I picked fights with the director. Keira started to hate me.

"It was stupid. I'm not very good at turning it on and off. It will take a long time for her to stop seeing me as arrogant."

The 'Debt' star admits it is hard to get away from his own thoughts, and entered a particularly dark place when filming thriller 'Texas Killing Fields'.

He added to the Metro newspaper: "I was a f**king maniac. I play a guy who's an angry racist dealing with dead bodies every day. I went off the rails, although I didn't know it at the time. I listened to a lot of murder tapes. I pinned pictures of murders up. Believe me, that is horrible to be around. It's always ringing in your head; it's in your being.

"You can't take a holiday from yourself. No matter where you go, you can't shake what's going on in your head."