Barr says she is running for president of the U.S. in the 2012 campaign.
She made the announcement during Thursday's taping of NBC's "Tonight Show."
Roseanne says she decided to let Jay Leno and his audience know first because, as she put it, Jay helped get Arnold Schwarzenegger elected as governor of California.
As for her announcement being a joke, Roseanne insists it's not.
The 58-year-old says she'll be a candidate for the Green Tea Party.