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What's My Letter? was a Season 2 Game Show hosted by Guy Smiley. Prairie Dawn was the show's guest, and the object of the game was to guess a letter of the alphabet, given some clues. She manages to get the answer right when she hears the prize will be a mouse - which frightens her!
This was one of the many tracks from The Muppet Alphabet Album that was lip-synched on the show.