Famously he was attacked by glove puppet Emu when children's personality Rod Hull was on his programme in 1976, and he also interviewed Muppets starMiss Piggy two years later.
Structurally, "The Muppets" is simple: Miss Piggy is the star of a late-night show, Kermit is her executive producer, and some assortment of available Henson characters, both new and old, are working behind the scenes.