There are a few possibilities for what you might be looking for:
* "The Muppets Tonight" (1996-1998): This show, starring John Henson, ran for two seasons and featured various guest stars. Perhaps you are thinking of this show?
* John Henson was known for his role as the host of "The Storyteller" (1988), but this aired before 1999.
* "The Muppet Show" (1976-1981): This classic show featured a large number of guest stars, but John Henson was not a regular cast member.
Could you please provide more information about the show you are looking for? Perhaps you remember the show's name, a specific episode, or a particular guest star?