Princess Diana said she would "go back to Charles in a heartbeat if he wanted her" just weeks before her death, a royal biographer has claimed.
Diana was tragically killed in a car crash in Paris in August 1997, the year after her divorce from Prince Charles.
While the Princess of Wales understood Camilla was the love of Charles' life, the pair were "on the best terms" before her death according to journalist Tina Brown, who penned The Diana Chronicles.
One month before her death, Diana met with Tina Brown, then editor of The New Yorker, and Vogue editor-in-chief Anna Wintour.
The trio had dinner at the glamorous Four Seasons Restaurant in New York where Diana reportedly admitted she would "go back to Charles" if she could.
Speaking to the Daily Telegraph, Ms Brown said: “At the end of Diana’s life, she and Charles were on the best terms they’d been for a very long time.
“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.
“It was definitely calming down, the boys were older. They talked about their philanthropies. And she had accepted Camilla.
“One thing she had finally done was really understand that Camilla was the love of his life, and there was just nothing she could do about it.
“But she said to me at that lunch that she would go back to Charles in a heartbeat if he wanted her.”
Diana, the former Lady Diana Spencer, was just 19 when she married Prince Charles at St Paul's Cathedral, London, in 1981.
The pair met for the very first time at Diana's family estate at Althorp House in Northamptonshire when Diana was 16 and Charles was 28.
The Prince of Wales was then dating Diana's older sister Sarah who he was visiting for a weekend of pheasant shooting.
Charles and Diana had their first son Prince William in 1982 followed by Prince Harry in 1984.
But their relationship was challenging with rumours of infidelities at both ends and they divorced in 1996.
Sources say the Prince never got over his former girlfriend Camilla Parker Bowles who he eventually married in 2005, becoming Duchess of Cornwall.
While still married to Charles, Diana famously said "there were three of us in this marriage so it was crowded" in interview.
But Ms Brown claims Diana admitted she felt lonely after her divorce from Charles.
She said: " Diana was desperately lonely. She still wished that her marriage could have survived.
“She didn’t say ‘I’m so happy to be divorced.’ She said ‘I think we would have made a great team’.”
According to the journalist, Diana had planned to continue her work as a philanthropist and allegedly held discussions about producing a documentary series.
She also reportedly spoke with Tony Blair, then Prime Minister, about a role in which she could represent the UK.
Ms Brown described Diana as a woman " very much on the cusp of trying to reinvent herself in a serious way".
She added: “She was a child when she got married but at this point she knew what she wanted."
