As part of his Sundance primer last December, Erik Davis gave us the low-down on the untitled Duplass Brothers project, which came to be titled Cyrus. John C. Reilly plays a lonely divorcee who goes about life pitifully, massacring Human League's "Don't You Want Me," and ruing the fact that his ex-wife (Catherine Keener) is going to marry someone else. But then he meets the woman of his dreams in Marisa Tomei. Unfortunately, it isn't until after he falls head over heels that he discovers the catch: She's got a really weird and dependent son (Jonah Hill).

It seems Tomei's Molly hasn't had a fella over since Cyrus has been born, which doesn't sound so bad, except that he's just plain creepy. (He watches them make out in the dark, and has some rather inappropriate bathroom habits.) This leads to drama and ... well ... it looks like a darker, funnier version of Step Brothers if it was, instead, based on boyfriend and girlfriend's son. (Then again, maybe this won't have a happy, symbiotic ending like Brothers.)

As Sundance kicks into gear, a trailer has popped up online, which you can see -- and most likely enjoy -- after the jump. Starting with a $3 short at Sundance, moving to The Puffy Chair, Baghead, and now Cyrus -- the Duplass Brothers (Jay and Mark) are going places. And how great is it to see Marisa Tomei in a role that doesn't require her to play the scantily clad paramour?!