Adam Scott has joined the cast of the new Judd Apatow produced, Adam McKay directed comedy Step Brothers. According to The Hollywood Reporter, Mary Steenburgen has also come aboard the Columbia Pictures film.

The plot revolves around two immature, coddled men who become stepbrothers and best friends, despite the irritation of their parents. Will Farrell and John C. Reilly are playing the brothers.

Scott will play the younger, successful brother of Farrell. Steenburgen will be playing the two men's mother. Shooting begins next month.