For the most part, each Muppet is performed and voiced by one person. But there are times when a character might be performed and voiced by separate people. Many characters created by Jim Henson's Creature Shop are voiced and performed by separate people, as were most of the characters in The Muppet Musicians of Bremen. On Sesame Street a number of Muppet characters have been voiced by non-performers, including various human cast members (like Matt Robinson as Roosevelt Franklin) and songwriters (like Christopher Cerf). For the most part vocals for music numbers are always recorded before taping/filming begins. However, in these cases characters are often still performed by their usual performers to pre-recorded tracks.
Sometimes, there are instances where performers can only voice their regular characters. This includes times when two or more characters from the same performer have dialogue in the same take of the same scene (such as when Big Bird and Oscar the Grouch, both performed by Caroll Spinney, are interacting), as well as times when a performer may be unavailable to be on set but is available to perform the voice at a separate time (such as Frank Oz in Muppet Treasure Island and Muppets from Space). There have also been instances where certain performers were no longer physically able to manipulate the puppets and could only provide voices, as was the case with Jerry Nelson during his later years of life and has been the case with Caroll Spinney since 2015.
A number of different methods are used when performers only perform the voices. In the early days, Jim Henson would pre-record the voices and the performers would perform to the pre-recorded tracks. Other times, a performer would perform somebody else's character, including the voices, live as a scene is being shot, while the voice would later be dubbed by the usual performer. Sometimes, the usual performer would record the lines live on the set while another puppeteer would perform the puppetry. In his last years of life, this was especially the case with Jerry Nelson and his characters.
When Stephen Colbert started a question on The Colbert Report to Frank Oz with "everybody knows you, of course, as being the voice of Miss Piggy, the voice of Grover, the voice Fozzie Bear, the voice of Animal, and the voice of Yoda..." Frank Oz interrupted to say "it's so weird." Colbert questioned "what's weird?" Oz replied "When you say 'the voice of.' So who does the character? Who does him physically?" Colbert, in character, replied with surprise saying "Oh, you do all that stuff!?!" Oz continued, "You're so use to animation where people just do the voices, but when performers of the Muppets do it, the voices are only 10% of it. The rest is 90% of it."
“In “Muppet Guys Talking,” all of the Guys agree that there’s a single “biggest misconception” about being a Muppet performer. Have any thoughts on what it might be? (We’ll have the answer tomorrow.)”
—Tweet from Muppet Guys Talking 1/9/18
““Who does the voice”? People always ask that. It’s the single biggest misconception about being a Muppet performer: Even longtime fans don’t always we don’t “just” do the voice -- we bring the character to life through a complex performance involving hands, arms, body and voice.”
—Tweet from Muppet Guys Talking 1/10/18
- Sesame Street Actors Who Performed Voices
- Muppets voiced by celebrities
- Creatures voiced by their puppeteer
- ↑ http://www.toughpigs.com/a-chat-with-jerry-nelson-part-1/ Tough Pigs interview with Jerry Nelson
- ↑ Frank Oz - The Colbert Report