They finally separated in 1992 after a tumultuous marriage that saw both engage in adultery.
While Prince Charles was ensconced with the future Queen Camilla (then Mrs Parker Bowles), Diana had several lovers.
One who has never been named was a married politician who was ‘famously’ charming, according to royal expert Tom Quinn.
He revealed in his 2021 book Scandals of the Royal Palaces that the politician, whose identity has never been revealed, was seen late at night in his boxer shorts by a member of Kensington Palace staff.
According to a former member of staff, the lover had ‘wandered off’ without his trousers and then was unable to get back to Diana’s room because a door had closed behind him.
He was left ‘red-faced’ as a staff member said good morning to him, Quinn recounted.
On other occasions, the lover would allegedly be forced to hide behind curtains or in Diana’s en suite bathroom when staff entered her bedroom, because the Princess was ’embarrassed’.
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One of Diana’s lovers – a married politician – famously got caught wandering the corridors of Kensington Palace in his underwear
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Charles and Diana in Seoul, South Korea in November 1992
Mr Quinn said he interviewed an unnamed former member of Palace staff, who said of Diana’s politician lover: ‘But he did get caught once – literally with his trousers down.
‘I don’t know how it happened but the staff laughed about it for weeks afterwards.
‘Somehow, he’s got up in the night in his shorts and wandered off until he found a door had closed behind him and he couldn’t open it to get back.
‘Diana quickly realised what had happened, and went to look for him, but he’d been spotted already by a member of staff who just said good morning to him and walked past while he froze, red-faced and trying to pretend nothing was amiss.’
One of Diana’s staff members, Kitty Power, used to help the Princess to stealthily bring her lovers into the palace.
She would use techniques including saying they were there to discuss work-related issues, Mr Quinn wrote.
Some of Diana’s lovers became high-profile. One was Captain James Hewitt, who the princess had a five-year affair with after the pair first met in 1986.
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Princess Diana presenting the Captain and Subalterns Cup to Captain James Hewitt after he led his Army polo team to glory at Tidworth, Wiltshire, in 1989
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A perhaps unlikely suitor was art dealer Oliver Hoare – a friend of Charles. He was married to French woman, Diane de Waldner de Freundstein
Diana confirmed the affair with Hewitt during her now-infamous Panorama interview in 1995 with journalist Martin Bashir.
A photo taken during their secret relationship shows Diana presenting the Captain and Subalterns Cup to Hewitt after he led his Army polo team to glory at Tidworth, Wiltshire, in 1989.
The relationship ended when he went to serve in the Gulf war.
She said at the time: ‘Yes, I adored him. Yes I was in love with him. But I was very let down.’
Another lover was art dealer Oliver Hoare – a friend of Charles. He was married to French woman, Diane de Waldner de Freundstein.
Oliver and Diana met at a Windsor Castle house party during Royal Ascot in 1985, Richard Kay previously reported.
The princess was said to be infatuated with the father-of-three and was accused of bombarding his family home with more than 300 telephone calls.
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Former lover of Diana, Hasnat Khan, a heart surgeon picturd in 1997
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Princess Diana and film producer Dodi Fayed, the son of now-disgraced Harrods owner Mohamed Al Fayed, in St Tropez in August 1997. The couple were killed less than a week later
Neither Mr Hoare nor Diana ever publicly acknowledged the relationship and the art dealer passed away in 2019 aged 73.
Another former lover was heart surgeon Hasnat Khan. The couple met at the Royal Brompton Hospital when Diana was visiting a friend who was recovering from a heart operation.
They then pursued a discreet, two-year affair which ended in the early summer of 1997.
Speaking in 2008, Mr Khan broke an 11-year silence about the Princess to say: ‘I found her a very normal person with great qualities.’
Diana’s final relationship was with film producer Dodi Fayed – the eldest son of now-disgraced Harrods owner Mohamed Al Fayed.
The pair dated for around two months before they were killed in a car accident in Paris in 1997.