What actors and actresses appeared in The Step Brother - 2010?

It seems you're asking about the movie "Step Brothers", released in 2008, not "The Step Brother" (which doesn't exist).

Here are the main actors and actresses who appeared in the movie "Step Brothers":

* John C. Reilly as Brennan Huff

* Will Ferrell as Dale Doback

* Richard Jenkins as Robert "Bob" Little

* Kathryn Hahn as Alice Little

* Mary Lynn Rajskub as Catalina

* Adam Scott as Derek

* Patrick Warburton as Derek's Friend

* Rob Riggle as Lance

* Andrew Daly as Greg

* David Koechner as Alistair

* Ken Jeong as Mr. Splat

* Jessica St. Clair as Lucy

Let me know if you have any other questions!