"He didn't want credit for it, or there was some kind of deal with his record company or whatever, so when it came time to sing the songs, he had a sound-alike singer," Matt revealed.
"He stood there and watched the guy, who was so nervous, who had to sound like Michael Jackson, and then he giggled."
Michael's character on the show was a balding patient in a psychiatric ward whom Homer Simpson (Dan Castellaneta) encountered.
More Simpsons Cameos
Michael Jackson isn't the only popular star who's voiced a character on The Simpsons. In fact, the show is notorious for inviting well-known people to be a part of the show.
Legendary musician Ringo Starr was featured in a season two episode of The Simpsons called Brush With Greatness. In it, he played himself.
The Red Hot Chili Peppers, Spinal Tap, Smashing Pumpkins, Cypress Hill, Sonic Youth, Peter Frampton, The Ramones, Johnny Cash, Metallica, Weird Al Yankovic, Barry White and other popular musicians have voiced characters on the show throughout it's time on the air.
Other noteworthy guests include Stephen Hawking, Elizabeth Taylor, Jon Lovitz, Gillan Anderson and David Duchovny, Stan Lee, Kelsey Grammar, Jon Stewart, George Takai, Ricky Gervais and more have taken part in The Simpsons as well.