Brooklyn Decker joins J.Lo in 'What to Expect'

Oh, baby! The big-screen adaptation of the popular parenting guide "What to Expect When You're Expecting" is shaping up to be quite the star-studded spectacular.

Jennifer Lopez, Chris Rock and supermodel Brooklyn Decker have all been cast in the film, which stars Cameron Diaz as a fitness instructor.

According to Entertainment Weekly, Lopez will play Holly, a woman who has trouble conceiving and decides to adopt a child from abroad; Decker stars as a NASCAR driver's wife whose worry-free pregnancy with twins inspires envy in  her fellow moms-to-be.

Meanwhile, Deadline reports that Rock will represent the guys, playing a man who lectures a group of expectant fathers about what it's really like to become a dad.

Ed Helms, Isla Fisher and Anna Kendrick will also appear in the ensemble comedy, which is set to film this summer for a May 2012 release.