A month before her death, Princess Diana told a royal biographer she would have gone back to her ex-husband Prince Charles “in a heartbeat.”

Former Vanity Fair editor Tina Brown told The Daily Telegraph the confession came in July 1987, when she had lunch with the 36-year-old princess at the Four Seasons Restaurant in New York. In the interview, Diana also told Brown, author of “The Diana Chronicles,” that she had finally accepted her ex-husband’s love for Camilla Parker Bowles.

Diana, dressed in a mint green Chanel suit, told Brown she and Charles had even started seeing each other socially again, and “enjoyed some laughs” as they discussed their various philanthropic efforts at Kensington Palace.

“At the end of Diana’s life, she and Charles were on the best terms they’d been for a very long time,” said Brown. “Charles got into the habit of dropping in on her at Kensington Palace and they would have tea and a sort of rueful exchange. They even had some laughs together.”

Brown, 66, is currently working on a sequel to her tell-all on the princess, entitled “The Palace Papers,” in which she claims Diana was “possessive” and “terribly demanding and needy.”