The Godfather star met the former airline attendant in London in 1987 and they had a fiery on-and-off relationship – with Robert, 75, initially filing for divorce in 1999, two years after they married!
They worked out their differences after an initial custody battle over their son, Elliott, now 20, and renewed their vows in 2004.
In 2011, they welcomed daughter Helen via surrogate.
A source told Page Six: “They are not living together at this time. De Niro and Grace are breaking up.”
As Radar has previously reported - the couple were said to have split years ago.
An insider said at the time: “If they did, in fact, divorce, it will be one of the biggest secrets ever in Hollywood history. Normally, you just can’t keep such a high-profile split quiet.”
However New York divorce attorney Julie Hyman noted couples can split on the down-low by agreeing to resolve the marriage in uncontested proceedings after “working things out behind closed doors” and “sealing the files.”
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