Sia's face doesn't make too many public appearances, but recently, the megastar paid Sesame Street a visit. Oscar, Elmo and Cookie Monster all rocked her trademarked wig as they learned about the letter 'S.'

"'S' is for songs, and I love songs/Don’t know what I would do without ‘em/I love songs so much/I wanna sing a song about ‘em." Very informative. Watch below.