Princess Diana would have married Dodi Al Fayed, and was possibly planning to live with him first, according to her stepmother Raine, the former Countess Spencer.
Speaking at the Paris inquest into the couple's deaths this week, Raine - who is a close friend of Dodi's father Mohamed Al Fayed and a director of his London department store Harrods - said she was sure the couple's relationship was much "deeper" and "closer" than "a summer romance".
The former Countess - who married Diana's father, Earl Spencer, in 1976 - said her stepdaughter, who she became close to following her husband's death in 1992, telephoned her a number of times after holidaying with Dodi.
"She said she had not been so happy for years. She was really blissfull," revealed the 78-year-old, describing one particular phone call which took place just two weeks before her death. "That was the moment when I really felt she and Dodi would get engaged and then married."
While she also believed "they may have even... lived together," Diana's former stepmother poured cold water on reports that the Princess could have been pregnant at the time of her death. "She was brought up in an old fashioned way," she said. "I think it would have been out of the question for her."