They should change the name to The Cameo Movie. The Muppets, starring Jason Segel and Amy Adams, has been almost completely taken over by celebrity guest stars. It's like The Love Boat, only there's no Isaac to kick around. New stars seem to be turning up every other day to make brief appearances in the film, and now you can add two more big ones to the line-up.
Ricky Gervais(The Office) and Emily Blunt have both agreed to sign on, according to THR. They'll be joining Jack Black, Zach Galifianakis, Jean-Claude Van Damme, Kristen Schaal(Flight of the Conchords), Alan Arkin, Billy Crystal, and French Stewart.
To be fair, pretty much every Muppet movie was overloaded with celebrity guests, so this is nothing new. There are a bunch of other unconfirmed cameos, including Lady Gaga, Sean Penn, Danny Trejo, and Ed Helms, but we'll just have to wait and see if those pan out.