Alicia Keys, Elmo and Kevin Clash.
Alicia Keys (b. 1981) appeared with Elmo on Sesame Street, singing a spoof of her song "Fallin.'" (First: Episode 4108) She also appeared with Elmo in a Healthy Moment to show how moving your body is a great way to be healthy and strong.
Keys later appeared in the Sesame Street holiday special Elmo's Christmas Countdown, singing "Do You Hear What I Hear?" with Elmo.
Keys claimed that the Sesame Disco! album, specifically the "Me Lost Me Cookie" and "Bein' Green" tracks, was among her earliest musical influences.[1]
In 2017, Keys collaborated with the Muppets for WE Day and posted a video of herself with Rowlf the Dog to Twitter. [1]