Bill Nye made his first appearance in the closing live-action segments of Back to the Future: The Animated Series (1991-92), performing science experiments in the video encyclopedia files that viewers could try for themselves at home. He had a line in one episode of the show.
These segments would eventually lead to Nye getting his own science show, Bill Nye the Science Guy, in 1993, in which he retained the lab coat and bow tie he had worn for Back to the Future: The Animated Series.
In 2013, Nye appeared as himself in an episode of The Big Bang Theory, "The Proton Displacement", as a new friend of Sheldon Cooper, only to later file a restraining order on him.
Nye's own show, Bill Nye the Science Guy, ended in 1998, the year that saw the release of The Powerpuff Girls, whose main character, Blossom, is voiced by Cathy Cavadini, who voiced Jennifer Parker in Back to the Future: The Animated Series.