Cosby was also a music composer, as he wrote the themes for The Bill Cosby Show (called Hikky Burr), The Cosby Show (Called "Kiss Me Honey"), as well as the theme music for his version of You Bet Your Life, and I believe, his last sitcom, simply called "Cosby" which reunited him with Phylicia Rashad and featured Madelyn Khan in her final role.
Actually, the theme for The Cosby Show (which was just "Kiss Me", and not "Kiss Me Honey") was co-written by Stu Gardner with Bill Cosby.