Princess Diana's Brother Claims He Was 'Gaslit' by King Charles Over Book Claims: 'I Was Really Shocked'

Princess Diana's brother, Charles Spencer, claimed he was duped by King Charles over the allegations he made in his upcoming book about his late sister.

In an interview that is set to air on September 21, Spencer, 62, chatted with ABC's Good Morning America about his new memoir, Swan Song: Diana, My Sister.

Spencer made several claims in the biography about the late Princess of Wales and the monarch's relationship, with one anecdote alleging Charles said the world would "forget" Diana "soon enough" after her 1997 death.

After the book's excerpt came to light on September 16, Buckingham Palace released a rare statement on the matter.

"While we do not comment on books as a matter of principle, 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 palace said.

During his interview with ABC, Spencer touched upon the royal family's response, noting: "It's not every day you're gaslit by a king, but I was really upset with that because I thought it was very, not only condescending, but not straight."

"What I said is straight and true. And what did they come back with? That. It doesn't say he didn't say it either. That's what I found interesting. I was really shocked, actually," the 9th Earl Spencer added.

Elsewhere in his book, Spencer also alleged Charles, 77, had an excited reaction when he heard Diana had died in Paris following a car crash.

"The phone rang constantly. Prince Charles caught me as I crossed the landing upstairs," Spencer penned. "Unlike my other callers, who were stunned, barely able to articulate their condolences and offers of help, he sounded giddily elated — like a lottery winner, I remember thinking at the time."

"He let me know he had informed [Princes] William and Harry of their mother’s death, first thing that morning, in their bedrooms at Balmoral [Castle in Scotland]," Spencer continued. "It all sounded strangely matter-of-fact, given the enormity of the disaster," he continued.

Another accusation in Spencer's memoir claimed Diana told him that Charles was "in love with his valet."

He then noted his sister did not mention the staffer by name, but that she was planning on divorcing Charles. While Diana and the sovereign split in 1992 after 11 years of marriage, they officially signed divorce papers in 1996.