Via Deadline Hollywood:

EXCLUSIVE: Here’s the part of the Lionsgate movie What To Expect When You’re Expecting that I’ll look forward to. Chris Rock is signing on to play a guy named Vic, who is the head of a group of expectant fathers who lectures them on what it’s really like to have a baby and become a father. The Kirk Jones-directed pic stars Cameron Diaz, Jennifer Lopez, Brooklyn Decker and Anna Kendrick (the latter two castings were announced today) in a mix of couples awaiting that stork visit. Rock will start working in late July, right after he finishes his run as the star of The Motherfucker With The Hat, which ends its Broadway run July 17. ICM is making Rock’s deal.

By: Mike Fleming
Source: http://www.deadline.com/2011/06/chris-rock-provides-the-411-for-guys-in-what-to-expect-when-you-are-expecting/