Okay, that doesn't have much to do with this thread. But it was somewhat appropriate, because he did do the song "Born to Add," which was a very well-known song of his.
He was not a muppeteer. He was a composer/lyricist, and he did voice, and he played the piano. Chris was his main muppet, but he also sang for Little Jerry and the Monotones. He sang Born to Add, Co-Operation, he sang on "Hey Food" by the Beetles, he did the voice of How Now Brown, and he performed the Rebel L, and he sang in some films. He's not a muppeteer, he's a musician, and he is very talented.