Many sitcom stars have found themselves in the charts. Some very succesful, such as Windsor Davies and Don Estelle (Stars of It Aint Half Hot Mum) singing Whispering Grass, which got to number one: http://youtube.com/watch?v=10dmK7O-KSY
But who remembers the duos second song to enter the charts that year, by the name of Paper Doll, which didn't do a Whispering Grass and get to number one, it got to number forty-one.
And most (in)famously of all who remembers Hylda Baker and Arthur Mullard singing Grease. Here is a video of its feature on 100 Greatest TV Moments from Hell of the song which is hilariously funny, but I'm laughing at Baker and Mullard because it is so shocking: http://youtube.com/watch?v=-niwpfm90nQ
Watch it, it is hilarious.