Matt Stone & Trey Parker at the Elton John Style Oscar post party. Los Angeles, 24/03/2002

The duo feared they would be going too far if they featured an animated Reeve sucking the stem cells out of fetuses in an episode of South Park, and ditched the idea.

But, when their Christian producer learned about the sick idea, she urged the animators to shoot the episode.

Parker recalls, "For a long time we're like, 'Maybe that's not cool.' So we actually went through a whole season not doing it.

"The next season we were out of idea and we're like, 'We've got the Christopher Reeve sucking stem cells idea, but that's really too brutal.'

"It just so happened that he was on (CNN show) LARRY KING LIVE that night, and our producer, who is, like, our sounding board because she goes to church every Sunday morning, was like, 'You know what? F**k him.'

"He really was taking up this cause of, 'Everyone needs to help me out.' Right before he died, I think he started going a little crazy, but he started getting really weird about it (stem-cell research)."