AceShowbiz - Aaron Eckhart and Nicole Kidman "irritated" each other on the tense set of their new film "Rabbit Hole" as they struggled to deal with the movie's disturbing subject matter. The actors play the grieving parents of a dead child in the harrowing film and Eckhart recently revealed he prepared for the role by taking part in a group counseling session with real life victims of family tragedies.

"The Dark Knight" star admits the sad story made life on set "uncomfortable" and he fell out with Kidman as they worked on their parts. He says, "She was irritated with me and I was irritated with her but that's the way movie-making is. For one day, are we not allowed (to fall out)? For half a day even?... It's so surprising to me when people are surprised that movie-making is sometimes tense and uncomfortable because inherently it's going to be."

"You're around tens of people or hundreds of people working on things that are imaginary and that come from the soul. You could be dealing with subject matter like prostitution, death, drugs, blah, blah, blah. How could you expect that not to be uncomfortable?"