The Muppets are coming back to the big screen, and they are bringing Christoph Waltz along for the ride. The actor is set to play the role of an Interpol inspector in the sequel, which has the Muppets get up to all sorts of hi-jinx in Europe. Waltz's role is said to be quite substantial, and not one of the many, many cameo's the movie is expected to have. My money is on him been the villain. Other main roles to be filled include a Russian femme fatale, and a new male lead, replacing Jason Segal who has declined to return.
Source: The Hollywood Reporter