From Entertainment Weekly
Another day, another pair of starry guests who’ll lend their talents to ABC’s "The Muppets".
The December 1st episode will welcome Joseph Gordon-Levitt and Dave Grohl for the episode “Going, Going, Gonzo,” which will ostensibly be the first time the new Muppets revival will see the Great Gonzo, Gonzo’s high-flying, daredevil alter ego.
Gordon-Levitt and Grohl will each play themselves, as stars on "The Muppets" are wont to do; the former will find himself involved in poker night with Scooter, Pepe, and the “cool” gang, while the latter challenges Animal to a drum-off.
It’s worth noting that both guest stars are already embedded in the Muppet/Henson world. Grohl appeared in the 2011 feature film, "The Muppets" as Animool, a knock-off of Animal in the Moopets, while Gordon-Levitt is set to produce and star in the upcoming "Fraggle Rock" movie for The Jim Henson Company.