The couple has split after 21 years of marriage, ET has learned. De Niro and Hightower share two children: son Elliot, born in 1998, and daughter Helen, born in 2011.
This isn't the first time De Niro and Hightower have broken up. They married in 1997, but split briefly in 1999, though never finalized their divorce. In 2004, they renewed their vows.
De Niro and Hightower, who met in 1987, have been pretty private about their relationship over the years. But in a 2013 interview withCBS News, the actor couldn't help but gush about his family, and his then-1-year-old daughter, Helen.
"She's so adorable. You just look at her, and it's all there. There's nothing... nothing else matters," he said.
The next year, Hightower told the Wall Street Journal what she had learned from her husband about business.
"Patience, really being, patience not panic, looking at all angles when starting up a business, always thinking there's a way to do this. There's another way to succeed at this," she said.
De Niro was previously married to Diahnne Abbott, from 1976 to 1988. He shares son Raphael with Abbott, and twin sons Aaron and Julian with his former girlfriend, Toukie Smith.