Charles Spencer gives cutting one-word theory on Princess Diana’s life if she hadn’t married King Charles

Princess Diana’s brother, Charles Spencer, believes his sister would have been “happy” if she had not married King Charles III.

The author gave the cutting one-word theory during an interview with Tina Brown at St. Peter’s Chelsea in New York City on Tuesday night, per People.

During the discussion about Spencer’s new book, “Swan Song: Diana, My Sister,” about his late sister’s life and legacy, he also argued that navigating life within the monarchy can be difficult for those who weren’t raised in it.

“I think there are certain people who find it very difficult to be inside of it. I think if you grow up in a royal family, it’s a lot easier than marrying into it,” he explained.

“If you look at the wives of those who’ve married in, it’s tough. It’s a way of thinking that is very specific.”

Charles and Diana met in 1977 and started off as family friends. Their relationship turned romantic in 1980 and by the following year, they were married.

The former couple welcomed their son Prince William in 1982 and son Prince Harry in 1984.

By the mid 80s, their marriage began to deteriorate as Charles’ current wife, Queen Camilla, became a significant presence in his life, and Diana became aware of their affair.

They separated in 1992 and the divorce was finalized four years later.

Diana died in a fatal road crash in Paris in 1997, along with her boyfriend, Dodi Fayed, and driver Henri Paul.

In his new book, Spencer makes several bombshell claims including that Charles sounded like a “lottery winner” when Diana died and that he said she would be forgotten “soon enough.”

The palace issued a blistering statement about the novel, saying that the loss of his sister clouded Spencer’s memory.

“His Majesty is mindful that the pain of fraternal grief can cloud reason, affect judgment and color memory in ways others do not recognize, even many years after such a loss,” the rep told Page Six.

However, Spencer doubled down on his claims, insisting to the BBC that he is “telling the truth” about Charles’ “monstrous” remarks about his ex-wife after her death.

Last week, Page Six reported that Harry is working on a documentary about his late mother for the 30th anniversary of her death and is trying to “woo” Spencer into participating in the film.