This holiday special goes back in time to show how Elmo's ancestors--not to mention those of Grover, Big Bird, Bert, Ernie, Oscar the Grouch and Cookie Monster--helped transform "the most unfriendly street in town" into the bright, kind, music-filled place it is today.
Audra McDonald
Zosia Mamet
Jim Gaffigan
Alan Muraoka
Suki Lopez
