India, Sept. 10 -- Rosie O'Donnell opened up about an end to her friendship with Ellen DeGeneres, describing it as one of the "most painful things that ever happened to me".

The 63-year-old Now and Then star recalled DeGeneres's 2004 Larry King Live appearance, in which she rejected ever knowing O'Donnell in a television interview, despite the fact that O'Donnell dubbed it as a decades-long friendship.

Appearing on Mamamia's No Filter podcast on September 7, O'Donnell said, "I couldn't believe it. I have photos of her holding my newborn babies. I knew her for 30 years."

"That was one of the most painful things that ever happened to me, in show business and my life," she added.

During her well-known 1996 appearance on The Rosie O'Donne...