Leon Redbone (1949-2019) was a singer, songwriter, and musician, known for singing music in the style of (or directly from) vintage 1920s and 1930s tunes.
On Sesame Street, Redbone sang several songs over film footage, including "Blueberry Mouth," "Have You Ever," and "What Do They Do When They Go Wherever They Go?"
Redbone began recording in the 1970s and was a returning musical guest on Saturday Night Live (including twice the first season) and The Tonight Show. He lent his musical stylings to commercials, the theme song to Mr. Belvedere, and guest spots on Between the Lions. He had a non-singing cameo as the stop-motion "Leon the Snowman" in Elf.