Operatic Lullaby

From Muppet Wiki

"Operatic Lullaby" was performed by opera singer Denyce Graves on Sesame Street. Accompanied by a chorus of barnyard animals, she sang the song to Elmo in an attempt to get him to go to sleep.

This song is a parody of "La Habanera" from Bizet's opera Carmen, which Graves had previously starred in.