Thompson is currently developing a new NBC sitcom, but Mitchell told TMZ that he will not be appearing in the series.
"Kenan does not want to be seen with me in any form of media, or even have my name mentioned around him," said the 34-year-old.
Mitchell insisted that there is "no bad blood" on his side, adding that he is "not upset" with Thompson.
"I respect his choice of wanting to make a name for himself solo," he claimed.
"I'm not declining a [Kenan & Kel] reunion, I know the fans love the show and would love to see some type of appearance with us... I just don't see that ever happening because of how he really feels."
"I think the show lives better where it's at, in the time it was in," he said. "I wouldn't want to taint that."
Thompson and Mitchell first appeared together on Nickelodeon sketch comedy series All That, before starring in sitcom Kenan & Kel from 1996 to 2000. The pair also shared the screen in 1997 film Good Burger.
> DS Icon: Kenan & Kel
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Watch a classic Kenan & Kel clip below: