In grand Muppet tradition, Jason Segel’s new The Muppets is shaping up to be a non-stop parade of celebrity guests, and some new names have now joined in: Foo Fighters’ Dave Grohl and Flight Of The Conchords’ Bret McKenzie. Grohl will appear briefly in the film as [SPOILER ALERT] a drummer filling in for Animal, who’s been forced to attend an anger management course. McKenzie, meanwhile, will re-team with the film’s director and the Conchords’ HBO show co-creator James Bobin, acting as the film’s music supervisor. McKenzie has reportedly already written several songs for the film, telling New Zealand site Stuff that he’s even recorded a few with Kermit The Frog and Miss Piggy.

And although the film’s newest addition to the Muppets, Walter, will be voiced by veteran puppeteer Peter Linz—and not, as rumored, Paul Rudd or Michael Cera—The Muppets obviously still has plenty of star quality, with the previously announced roles for Amy Adams, Rashida Jones, and Chris Cooper, plus cameos (some confirmed, some still just rumored) from Alan Arkin, Jack Black, Emily Blunt, Billy Crystal, Lady Gaga, Zach Galifianakis, Ricky Gervais, Donald Glover, Ed Helms, John Krasinski, French Stewart, Eric Stonestreet, Wanda Sykes, Danny Trejo, and Jean-Claude Van Damme.