It's no secret that Judd Apatow likes to cast his family -- actress Leslie Mann and their two daughters -- in his movies, often to hilarious effect. But the prolific director of "This Is 40," opening in theaters Friday, has also cast the same set of collaborators in the dozens of productions he's helmed, written and produced over the past 20 years. Here, we present the Apatow clan, Hollywood's newest "it" family.

Loading Slideshow...
  • Maude and Iris Apatow

    <strong>Number of Apatow Projects:</strong> 3 <strong>Best Known For: </strong>Being Apatow and Mann's adorable daughters

  • Leslie Mann

    <strong>Number of Apatow Projects:</strong> 5 <strong>Best Known For: </strong> "Knocked Up"

  • Paul Rudd

    <strong>Number of Apatow Projects:</strong> 5 <strong>Best Known For: </strong> Looks like it will be "This is 40"

  • Seth Rogen

    <strong>Number of Apatow Projects:</strong> 11 <strong>Best Known For: </strong>"Knocked Up"

  • James Franco

    <strong>Number of Apatow Projects:</strong> 3 <strong>Best Known For: </strong> "Pineapple Express" and "Freaks and Geeks"

  • Steve Carell

    <strong>Number of Apatow Projects:</strong> 3 <strong>Best Known For: </strong> "The 40-Year-Old Virgin"

  • Bill Hader

    <strong>Number of Apatow Projects:</strong> 5 <strong>Best Known For: </strong> "Superbad"

  • John C. Reilly

    <strong>Number of Apatow Projects:</strong> 3 <strong>Best Known For: </strong> "Walk Hard: The Dewey Cox Story"

  • Jack McBrayer

    <strong>Number of Apatow Projects:</strong> 3 <strong>Best Known For: </strong> "Forgetting Sarah Marshall"

  • Kristen Wiig

    <strong>Number of Apatow Projects:</strong> 4 <strong>Best Known For: </strong> "Bridesmaids"

  • Martin Starr

    <strong>Number of Apatow Projects:</strong> 5 <strong>Best Known For: </strong> "Freaks and Geeks"

  • Jonah Hill

    <strong>Number of Apatow Projects:</strong> 7 <strong>Best Known For: </strong> "Superbad"

  • Will Ferrell

    <strong>Number of Apatow Projects:</strong> 4 <strong>Best Known For: </strong> "Anchorman"

  • Jason Segel

    <strong>Number of Apatow Projects:</strong> 5 <strong>Best Known For: </strong> "Forgetting Sarah Marshall"

  • David Koechner

    <strong>Number of Apatow Projects:</strong> 5 <strong>Best Known For: </strong> "Anchorman"

  • David Krumholtz

    <strong>Number of Apatow Projects:</strong> 4 <strong>Best Known For: </strong> "Freaks and Geeks"

Also on HuffPost: