ABC TV bosses axed the revived comedy earlier this year after Barr was caught up in a racism drama following an ill-advised tweet attack on President Barack Obama's former aide Valerie Jarrett, but the show will continue as "The Conners" - without Roseanne.
Fans have been wondering how TV bosses will pick up the show without the comedienne, and now she reveals the TV Roseanne will die after suffering an opioid overdose.
"They have her die of an opioid overdose," she tells Brandon Straka's YouTube show Walk Away. "There's nothing I can do about it. It's done. It's over. (But it) so cruelly insults the people who loved that family in that show."
Barr recently claimed she quit the TV comedy, so her cast and crew could continue with "The Conners".
"I just have to be neutral and walk away," she said. "I did walk away, so people can keep their jobs."