Vieira, now with NBC's "Today" show, said she "actually was surprised" even though she had "heard rumblings in the past."
"It appears that (O'Donnell is) having a really good time and I thought probably she would stay on," Vieira said. "I don't know exactly what happened. I take her on her word that they couldn't reach an agreement on the contracts."
Jones Reynolds, who is moving on to "Court TV," said she learned of O'Donnell's June departure from a person sitting next to her on an airplane.
"I had no idea and when I landed, of course, I found out that she announced it," Jones Reynolds said. "I wish her the very best in what she is doing next as I do for all the ladies over there, and I know whatever they do next is going to be great."