So I saw a thread on a Fall Guy remake movie. This got me to think about a subclass of TV where the star or members of the cast actually sing the lyrics to the show's theme song. I could list off a $#!+load, but I'd rather see a thread that explodes with originality. So please post a video (if you can) or a mention of a show where the song is sung by a cast member.
"Space: The Final Frontier" for Trek does not count.