Guest starring in your own TV show?

[Earl_Snake-Hips_Tucker]

Gavin McLeod guest-starred on “Love Boat” multiple times as Capt. Stubing’s brother, who was credited under a fake name.

[That_Don_Guy]

@Jay_Z

@That_Don_Guy

The only time I remember someone being given two separate voice credits is when Dan Castellaneta was also credited as “Jerry Seinfeld voice impersonated by.”

I imagine that may have been done for legal reasons. The Simpsons had frequent guest stars and I can’t think of a lot of situations where a “real life” person appeared and it wasn’t the actual person. Though now that I think of it, they did it with George HW Bush.

As @Q.Q.Switcheroo pointed out, Jay Mohr was credited “as Christopher Walken” in one episode. However, more recently, when this was thought necessary, there is a “Certain Celebrity Voices Impersonated” generic credit - for example, for Pele in the Season 9 episode “The Cartridge Family.”
I was about to say that I thought the reason it wasn’t done for George H.W. Bush (or Gerald Ford, in the same episode) was, Presidents are considered “public domain figures”, but I don’t think that applies to first ladies as well, and Barbara Bush was voiced in the same episode. (Also, it turns out that only the Presidential portraits are public domain.)