Judd Apatow’s upcoming movie, This Is 40 (out Dec. 21), is a family film. Not that kind of family film: it’s still rated R, and it’s still a Judd Apatow movie. Picking up a subplot from 2007′s Knocked Up and running with it, This Is 40 focuses in on side characters Debbie and Pete, played by Leslie Mann and Paul Rudd, and their family—and what it means to be 40 years old and kind of, sort of, a little bit a grown-up.
It’s a family movie in another way, too: Leslie Mann is Apatow’s real-life wife, and the kids in the movie are their real-life kids, Maude (14) and Iris (10). Joel Stein goes behind the scenes with the Apatow clan in this week’s issue of TIME—and he finds that the kinship isn’t confined to blood relations.
“You get sort of a family feeling,” veteran Apatow actor Chris O’Dowd told Stein. “Family is wrong. Cult. It’s got more of a culty feeling.”
Read the full story in this week’s issue of TIME.