From Muppet Wiki

Chubby Checker (b. 1941, real name Ernest Evans) is a popular singer best known for his #1 single, "The Twist", which led to a national dance craze. It was so popular, that it actually hit the #1 position twice, in 1960 and 1962. Other dance records followed, but none had the impact of the original.

Checker guest starred on Sesame Street in the 1990s, appearing in the celebrity version of "Monster in the Mirror."