People.com said Saturday that O'Donnell made the revelation regarding her partner of five years while talking on her Sirius Satellite radio show with pet psychic Sonya Fitzpatrick.
O'Donnell told Fitzpatrick on Friday that she got her dog, Misty, after Carpenter departed their home.
"What happened (was) when Kelli moved out two years ago, I got the dog. Because I wanted another child or something to love. And I got the dog," O'Donnell, 47, said.
People magazine said O'Donnell commented in October how she and Carpenter were attempting to mend their relationship.
"We're a family, we remain a family. ... Kelli and I love each other very much, and we are working on our issues," the "Rosie Radio" star said in an Oct. 20 interview. "Those are the only words I am ever going to say. Ever. And that is something that has been agreed upon by all parties."