"Sing" is a 1971 song written by Joe Raposo for the children's television show Sesame Street as its signature song. In 1973, it gained popularity when performed by Carpenters, a #3 hit on the Billboard Hot 100. Raposo was a staff songwriter for Sesame Street, and the song became one of the most popular on the program, sung in English, Spanish and sign language. In its initial appearance, it was sung by the show's adult human cast members (the most frequent lead singer was Bob McGrath) and Muppets, including Big Bird.