On Movies: A character actor steadily plies his craft

In Cyrus, John C. Reilly stars as a socially inept guy named John, long divorced from his wife (Catherine Keener), but having trouble letting her and her new husband alone. John has a decent job (he's a film editor), but no life, no girlfriend.

And then, at a party, after several bumbling and humiliating exchanges, he meets a woman. Her name is Molly. She is played by Marisa Tomei, and she and John bond while singing along loudly, and dancing badly, to the Human League's '80s hit, "Don't You Want Me."

Suddenly, the future looks brighter. He can hardly believe his luck. She seems genuinely keen on him. And then John meets the 21-year-old guy that lives with Molly, her son, an intense piece of work named Cyrus - played, in an intensely funny and sometimes discomforting performance, by Jonah Hill.

"Oh, yes, it's uncomfortable," Reilly says. "It just is. Like, how do you broker that situation? When you're dating someone who has little children, you can shelter them. But when someone's 21 years old, there's got to be that moment where they're looking across the breakfast table at each other, the kid and the new boyfriend, and it's like, 'You are having sex with my mother and that is not right!' "

Directed by Jay and Mark Duplass - sibling perpetrators of the highly esteemed, low-budgeted The Puffy Chair and the mumblecore horror pic Baghead - the decidedly edgy Cyrus was dreamed up with Reilly in mind. The film opened Friday at the Ritz Five and Rave Motion Pictures Ritz Center.

"Jay and Mark wrote this script, and we met and they said, 'Well, we hope you want to play this character, because if you don't, we're not going to make this movie,' " recalls Reilly, in Philadelphia recently. "'It's not like we can replace you with someone else - you're the only person we're thinking of.'

"And that was like, Whoa! All right. I guess I better do it then."