Cherubic Jack Black doesn't leap to mind as someone to play a real-life murderer. Yet that's exactly the role he tackles in "Bernie." Reuniting with his "School of Rock" director Richard Linklater for the off-kilter true-crime musical comedy, he plays Bernie Tiede, a big-hearted funeral director who was a pillar of his East Texas small town. In 1996 he snapped and killed his longtime companion Marjorie Nugent, a wealthy, malicious, widely detested widow played in the film by Shirley MacLaine. In a phone interview last week, Black explained the creative challenges of playing his challenging part for real, and for laughs.

Q: When you were approached about the project, were you befuddled about what the tone was going to be?

A: You've got to tread lightly when you're going for a dark comedy based on real events. It's tricky. There were deep, emotional scenes that were challenging and there was some concern that I wouldn't be able to pull it off. But I'm actually a pretty emotional guy even though I'm known for being a clown.

Q: A lot of what happens to Bernie is about bottling up humiliation. Did you identify with those feelings?

A: When he's mistreated he doesn't tell people how he feels. He just bottles it up and puts it away. Because it's so important that he be liked. I have that germ in me, too. It bothers me a lot if I feel like someone's mad at me. I'll lose sleep over it and try to make it right. He got trapped in an abusive relationship. There are thousands of murders that happen every year between loved ones, husbands and wives and family members. There's almost always a history of abuse and the answer to "why they don't just leave" is complicated.

Q: You visited Tiede in prison. What was that like?

A: He was the most popular guy in the prison. He was teaching classes and making the prison a better place to be. I wanted to meet him face to face. I wanted to listen to his accent and see the way he walked and talked and moved. I asked about what his relationships were like, what his life was like, what would lead him to this horrible crime when he seemed the least likely to commit a crime like that. When you meet him, you definitely get the feeling he's not a danger to society. But he did a crime and he did deserve to do time. Did he deserve a life sentence? I don't think so, but sometimes that's what happens in a court system.

Q: You have a moment of emotional breakdown after the murder. How did you prepare for such a starkly dramatic scene?

A: You just close your eyes and imagine yourself in that horrible situation. I've had times in my life that I've done things that I've really regretted. Magnify that by a hundred, because this is something that I've never touched in my life but can relate to in a small way.

Q: Did you sing for Shirley MacLaine?

A: I was just practicing the songs from the movie, and lots of gospel. She was really into it, saying we have to take this movie to Broadway as a musical. Can you imagine?