He also said the couple discussed marriage but he never proposed because he felt her fame would make his life "hell" since they would never be able to do normal things together.
Surgeon Hasnat Khan has refused to testify at the coroner's inquest into the 1997 deaths of Diana and boyfriend Dodi Fayed, but the jury heard a statement he made to London's Metropolitan Police on Sept. 24, 2004.
He refuted Mohamed al Fayed's claim that Diana was pregnant when she died, saying she was "very particular" about taking birth control pills during the two years they had an intimate relationship.
Khan said the relationship ended after Diana's first visit to France as a guest of the Al Fayed family in July 1997. He said Diana did not seem "her normal self," and he thought she had "met someone else from the Mohamed al Fayed contingent."
"At a second meeting, she said it was all over between us, but she denied there was anyone else."
He said he was unaware of her romance with Dodi Fayed before the couple's death in a car crash in Paris on Aug. 31, 1997.
"It was only when I heard the news on the radio that I learned about Dodi," Khan said.
Rosa Monckton, who joined Diana on an Aug. 15-20 holiday in Greece, testified earlier that she believed Diana "was really missing Hasnat and that I think Dodi was a distraction from the hurt that she felt from the breakup of that relationship."
Diana's butler, Paul Burrell, testified that she referred to Khan as "The One," a term she used for no one else.
Khan said the princess' fame was an obstacle in their relationship.
"My main concern about us getting married was that my life would be hell because of who she was," Khan said.
"I knew I would not be able to live a normal life and if we ever had children together, I would not be able to take them anywhere or do normal things with them."
He told police that Diana was not used to doing everyday things that most people take for granted.
"For example, we once went to the pub together and Diana asked if she could order the drinks because she had never done so before," he said. "She really enjoyed the experience and chatted away happily to the barman.
"On another occasion we had to queue to get into Ronnie Scott's jazz club. She later said she loved queuing as you get to meet so many people."
Although marriage was discussed, and Diana scouted locations - including Pakistan, South Africa and Australia - as possible places to live, Khan said there was never a formal proposal.
He was also surprised that Diana was not wearing a seat belt when her car crashed in a Paris tunnel because "she was always very particular about putting her seat belt on."
Diana met Khan when visiting a patient, and he said a friendship grew on subsequent visits.
"We were chatting one day and I mentioned that I needed to go to my uncle's house in Stratford-upon-Avon to pick up some books," he said.
"I did not think for one minute that she would say yes, but I asked her if she would like to come with me. I was very surprised when she said she would.
"We drove there together and Diana met my aunt and uncle. We had dinner in a restaurant and then drove back to London. ...
"After this, our friendship turned into a relationship."
By Robert Barr