Michael Jackson
Wikisimpsons - The Simpsons Wiki
In the first episode of the third season ("Stark Raving Dad"), Homer gets admitted to a mental asylum for wearing a pink shirt to work. While in the asylum, he meets a fat white guy who professes to be "the small black guy" (according to Bart), Michael Jackson. Although at the time the public was told that Michael Jackson did not do the voice for this character, it was later revealed that he had but he did not want any credit for it.
In this episode he and Bart composed and played the song "Happy Birthday, Lisa" as Lisa's birthday present.
The real Michael Jackson is a huge fan of the Simpsons.