For Judd Apatow, directing is just the fun little thing he does between masterminding the modern age of cinematic comedy.

"This Is Forty," the fourth film by the successful writer/director/producer, will arrive on the tails of his previous flicks "40-Year-Old Virgin," "Knocked Up" and "Funny People," along with producing efforts like "Anchorman," "Forgetting Sarah Marshall" and the recent hit "Bridesmaids."

Quite a resume.

The new movie is a spin-off of the Paul Rudd and Leslie Mann characters from "Knocked Up," following the couple as they move into the golden age of life. Apatow is reaching far and wide for the perfect cast, signing Megan Fox and comic legend Albert Brooks to the picture -- and now The Playlist reports that Chris O'Dowd, Lena Dunham, Charlyne Yi and Wyatt Russell have also joined the movie.

While not all familiar faces, the slew of new talent has enough street cred to deliver to notch comedy on par with what we expect from Rudd and Mann. O'Dowd is known overseas for his work on the British comedy "The IT Crowd," but made a big splash as the cop in "Bridesmaids." Dunham has an HBO show in the works with Apatow after successfully launching herself into stardom with the indie hit "Tiny Furniture." Yi appeared in "Knocked Up" and her own film "Paper Heart" -- she'll once again play Seth Rogen's stoner friend Jodi (although Rogen is not set to appear in the film).

The big unknown is Russell, son of Kurt Russell and Goldie Hawn, whose previous credits are limited. According to the report, Russell will play a hockey player in the film -- someone to go toe to toe with Rudd, perhaps?

With a cast assembled of players familiar with Apatow's signature style of heartfelt comedy, "This Is Forty" should be another entry that delivers the poignant laughs. The movie shoots this summer and is already slated for a December 21, 2012 release.