From Muppet Wiki

En Vogue is an award-winning, all-female R&B group from California. Members Cindy Herron, Maxine Jones and, Terry Ellis appeared in the television special Elmopalooza to perform an update on "I Want a Monster to Be My Friend" with Zoe, Cookie Monster, Frazzle, and The Two-Headed Monster. Their recording of the song is also available on the soundtrack.

The group previously appeared on Sesame Street to perform "Adventure". One of the group's appearances was included in Sesame Street All-Star 25th Birthday: Stars and Street Forever!