No one can substitute Justin Timberlake, but he’ll at least be playing one in forthcoming comedy “Bad Teacher.” The pop-star/actor -- plus Molly Shannon and Eric Stonestreet -- join a cast of Cameron Diaz, Jason Segel and Lucy Punch in the Jake Kasdan-directed flick.

Timberlake plays what Columbia Pictures calls a “key role” as a substitute teacher and “the scion of a watch fortune.” Lensing is scheduled to start this month, with Diaz in its lead role as a cussing, gold-digging junior high teacher, who sets her sites next on the school’s star teach.

Lee Eisenberg and Gene Stupnitsky are penning the script.

Timberlake will soon be seen in another Columbia film, David Fincher’s “The Social Network,” due in October.



“With Justin, Molly and Eric, joining Cameron, Jason, Lucy and the rest of this dream comedy cast, we couldn't be more excited about this movie. We love what we’ve seen of Justin's performance in David Fincher’s The Social Network and he is a perfect match for this role,” said Columbia prez Doug Belgrad.