The pseudo spin-off to Forgetting Sarah Marshall gets some supporting stars

From Variety:

Elisabeth Moss, Rose Byrne and Sean Combs are heading to the Greek for Universal Pictures.
The trio has joined the cast of the Nicholas Stoller-helmed comedy "Get Him to the Greek." Jonah Hill and Russell Brand have already signed on to topline.
Penned by Stoller, the story centers on the story of a record company intern (Hill) with two days to drag an uncooperative rock legend (Brand) to Hollywood for a comeback concert. Moss will play the girlfriend of Hill's character, while Byrne will take on the role of Jackie Q, a scandal-plagued pop star and love interest of Brand's character. Combs will portray a record company executive.
Judd Apatow is producing alongside David Bushell and Stoller. Rodney Rothman and Phil Eisen are exec producing.
Moss, a regular on AMC's "Mad Men," is currently shooting Columbia Pictures' romantic comedy "Did You Hear About the Morgans?"
Byrne, who stars on FX's "Damages" and whose bigscreen credits include "Knowing," will next be seen in Fox Searchlight's "Adam."
Combs, best known for his music career, most recently exec produced Fox Searchlight's "Notorious."
-If they let Brand and Hill loose, this could be a lot of fun...