O’Donnell’s new romance comes nine months after the end of her second marriage.
Tatum and Rosie have been quietly dating for several weeks now.
Rosie lives in the Hudson River village of Nyack, New York, while Tatum splits her time between New York and California.
O’Donnell and O’Neal were spotted together in early August at the Broadway musical Hamilton and a few days later at Da Silvano restaurant in New York.
An eyewitness said that “Rosie looked great, happy and relaxed.”
Tatum, who was the youngest person ever to win an Oscar at the age of 10 for the 1974 film “Paper Moon”, has reportedly been spending time at Rosie’s compound this past month.
Tatum, who has three grown children from her eight-year marriage to tennis champ John McEnroe, announced she was now ‘dating mostly women’ in an interview with People magazine in May.
O’Neal said, “Women are the most amazing creatures on earth. They’re gentle and also more intelligent than the men that I’ve met recently.”
At that time she said, “I don’t have a steady right now, but I look forward to it”.
O’Neal, who has fought a life-long battle with heroin said she experimented with women in the past, but it is only now she is drug-free that she has gone further.
She explained, “Now I’m clean and aware and alive and interested in the world. Dating women is exciting to me, and this is turning me on.
“I dated in the heterosexual world up until about four years ago, when I started thinking about dating women – just thinking about it.”
Since they have been together, Rosie, 53, and Tatum, 51, have regularly retweeted each other’s Twitter messages and news about themselves.
On August 21, Rosie posted a link to Tatum’s Harper’s Bazaar piece.
Rosie has been married twice since she came out as a lesbian in 2002. Her first marriage to Kelli Carpenter fell apart after three years.
She then married Michelle Rounds in 2012 and they adopted one child. They split in November last year.
Just weeks ago, Rosie’s second oldest child, Chelsea, went missing on August 11 and was later found hiding in the attic of a convicted heroin dealer who she met through Tinder.
Rosie’s father, Edward, died on August 23. The following day, Chelsea moved out of the home in Nyack to go to live with her birth mother in Wisconsin.
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