SS49 AndyGrammer

Andy Grammer (b. 1983) is a singer and guitarist who appeared on Sesame Street during Season 49, singing "Plan the Play" in Episode 4912.

Grammer previously appeared at the Annual Sesame Workshop Benefit Gala in 2017 (at one point joining the Muppets and other guests for "Sing") and participated in the Spread Kindness, Share the Laughter campaign (in a solo video, sans Muppets).

Wikipedia has an article related to: