Muppets Most Wanted, the sequel to the 2011 Muppets-reboot, is predictably filled with celebrity cameos. That's standard fare for the Muppets. However, some of them might have you going, "I know that guy, but what's his name?"
That's not to say there aren't instantly recognizable cameos in the movie. Lady Gaga and Tony Bennett show up in the opening number. Christoph Waltz performs a waltz with Sweetums. Celine Dion sings with Miss Piggy. If you ever wanted to see Danny Trejo, Jemaine Clement, and Ray Liotta perform the opening number from A Chorus Line, this is the movie for you. (Of note: Liotta was in 1999's Muppets from Space.)
But there are also a number of cameos we almost hesitate to call cameos since they are made by recognizable actors who are not necessarily household names. Most of the actors in question are British, likely a result of the fact that the movie was filmed in England and directed by Englishman James Bobin. For reference, here are the people you are going to want to be able to name in order to impress your friends on the way out of the theater.
Cameo role: A woman who yells out of a window. She came and went so quickly that I almost thought she was Bernadette Peters.