Royal expert Tom Quinn just dropped quite a bomb when he revealed a story about two construction workers once catching Princess Diana sunbathing naked.

Quinn just released his new book “Kensington Palace: An Intimate Memoir from Queen Mary to Meghan Markle,” in which he talked to people who had worked with the royals for years. It was during these discussions that Quinn learned some shocking stories about Diana.

“It’s surprising,” Quinn told Fox News. “I was more surprised than anyone when I discovered — you know, there are so many stories about the late Diana, Princess of Wales. I thought, ‘Well, there can’t be many more that people haven’t heard.’ But in talking to various people, I found some wonderful stuff.”

He went on to explain that Diana loved sunbathing in the nude in her rooftop garden in Kensington Palace, where she thought she was safe from paparazzi and helicopters.

“She loved sunbathing,” Quinn said. “This was the ‘90s. There wasn’t so much worry about cancer scares and so on. She used to sunbathe on a flat roof at Kensington Palace.”

One day, however, things went very wrong when Diana was sunbathing in the buff.

“Somebody had done something with one of the screens,” Quinn explained. “There were small trees in troughs around the flat roof and she hadn’t noticed it had been taken away. So she stood up with no clothes on and then immediately realized two builders who were working a hundred yards away. She was eye to eye with them. They’d seen her standing up and no clothes on. And the two builders immediately just bowed and turned away.”

“They may have just been builders, but they were gentlemen all the same,” he added.

Quinn heard other stories about Diana as well, as aides in Kensington Palace recalled that they often heard her fighting with her husband, Prince Charles.

“You could hear them rowing almost from the day they moved in,” one staffer told Quinn.

This did not surprise Quinn in the slightest.

“They were almost maneuvered together because she was from a very ancient English family,” he explained. “And Charles needed someone who was young [who] could have children. I’m not sure they were well-suited, but they were maneuvered together by the royal establishment.”

Most of the fights were over Charles’ alleged mistress, Camilla Parker-Bowles.

“If you look at the film of the wedding day, there’s a tension and unease,” said Quinn. “… Camilla and Charles had a relationship before Diana and I think Diana rather naively thought that the relationship would end. It was never going to happen… Camilla actually encouraged [Charles] to marry Diana because they thought Diana would be complacent. She was timid. They thought she would just accept the fact that Charles and Camilla would carry on seeing each other.”

“They completely underestimated her,” he continued. “In fact, someone said to me that if you look very carefully at the wedding film, you can see Diana glance across because Camilla was actually there in the church when they got married… You can see from the outset that Charles and Diana’s marriage was doomed because the cracks were there from the beginning.”

The couple divorced in 1996, and Diana tragically died a year later in a car crash at the age of 36. Though it’s been over twenty years since her death, Diana is still dearly missed by millions of royal fans to this day.