King Charles and Prince William Are 'Absolutely Furious' Over Charles Spencer's Shocking Princess Diana Book Claims: Royal Expert

King Charles and Prince William are said to be angry over the allegations Charles Spencer made in his recent book, Swan Song: Diana, My Sister.

According to several royal experts, the monarch, 77, and the Prince of Wales, 44, are none too happy with what the 9th Earl Spencer, 62, penned in his book about the late Princess of Wales' final years.

Among the claims Spencer penned in his memoir about Charles, included how the monarch reportedly sounded "sounded giddily elated — like a lottery winner" when he first heard Diana died.

The author also alleged the sovereign said people would quickly "forget" Diana soon after she passed away. Diana died in August 1997 at the age of 36 due to injuries she sustained in a Parisian car crash.

According to royal expert Hilary Fordwich, William and Charles are "absolutely furious" over Spencer's book.

"[William's] public silence regarding this matter is admirable," she told Fox News on September 28. "The pain Spencer is causing William has backfired as he’s being accused of monetizing his sister’s memory."

Expert Kinsey Schofield also gave her two cents to the news outlet, noting Charles has "lived with being cast as the villain in the Diana story for decades."

"Unfortunately, being portrayed as the bad guy in somebody else's version of this story is not new territory for him. For Prince William, there is an additional sense of betrayal. This is his uncle, who famously stood at Diana's funeral and promised that her 'blood family' would protect William and [Prince] Harry," she added.

Diana and Charles tied the knot in 1981 and divorced 15 years later, with their relationship often being marred by public scandal and scrutiny.

"William now has to watch that same uncle reopen some of the most traumatic events of his childhood and hear extremely damaging allegations against his father," Schofield said.

Charles is also reported to be in "full damage-control mode" following the release of Spencer's book earlier this month.

An insider previously told RadarOnline.com the Palace is "acutely aware of how damaging an allegation of this nature can be because Diana remains such an important figure to millions of people."

"There was a feeling that allowing such a serious claim to circulate completely unanswered would risk it becoming accepted as fact," the source went on. "The response reflects just how seriously this is being taken, and Charles is now in full damage control mode."