Prince William "simply can't forgive" Prince Harry for the way things have unfolded for the royal family following his exit.
The claim was made by Vanity Fair's royal correspondent and author Katie Nicholl in her new bombshell book titled "The New Royals: Queen Elizabeth's Legacy and the Future of the Crown." While the book is expected to drop on Oct. 4, Vanity Fair published an excerpt on Wednesday.
Nicholl, who appeared on "Dan Wootton Tonight" Thursday, claimed that the rift between the brothers has deepened over the years.
"William simply can't forgive [Harry], not just for his behavior and what he's done and how he's done it, but look at how much now rests on William," Nicholl explained. "He always thought Harry would be his wingman. Now he's doing it on his own. Thank goodness he's got Kate by his side."
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In her book, Nicholl pointed out that "there were raised eyebrows at the palace" after Harry spoke of his meeting with Queen Elizabeth II on the "Today" show. During his appearance in April of this year, the 38-year-old said he wanted to ensure that his grandmother was "protected" and had "the right people around her."
"It wasn't clear whether Harry was referring to his father and William or the aides who were closest to the queen - such as her private secretary, Sir Edward Young, her personal adviser and in-house dress designer, Angela Kelly, and trusted courtier Paul Whybrew," Nicholl wrote. "It seemed Harry's drive to win back some of the trust that had been shattered post-Oprah was dashed. There was also still the matter of what Harry plans to disclose in his forthcoming memoir."
"For Charles and William, the situation with the Sussexes hasn't just been hurtful and upsetting on a personal level," she claimed. "There have been real repercussions, particularly for William, whose young family has been thrust into the spotlight prematurely. He always expected Harry would be his wingman; there was a long-term plan in place for the brothers to work together and support one another."
The Duke and Duchess of Sussex stepped back as senior royals in 2020 over what they described as the British media's intrusions and racist attitudes towards the former "Suits" star, 41. The couple's decision was dubbed "Megxit" by the press.
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"After Harry announced their departure, William summoned aides to address the future, in what has been referred to by some in William's circle as the 'Anmer Summit,'" Nicholl claimed. "But William and Kate [Middleton] also felt a sense of relief that 'the drama was gone' when Harry and Meghan left, as a source told me. To this day, William still cannot forgive his brother."
In the wake of quitting royal duties, the Duke and Duchess of Sussex gave an explosive TV interview to Oprah Winfrey, in which the couple described painful comments about how dark their son's skin might be, before his birth. The duchess also talked about the intense isolation she felt inside the royal family that led her to contemplate suicide. When Winfrey asked the duchess about tabloids insisting she made Middleton cry, Markle alleged it was William's wife who made her shed tears before marrying Harry.
"A lot of horrible things were said during the Oprah interview but what crushed Prince William was the fact that Harry would allow any criticism of his wife, the Princess of Wales, on international television," Kinsey Schofield, royal expert and host of the "To Di For Daily" podcast, claimed to Fox News Digital.
"That exchange about 'crying' has created the worst animosity between the brothers because Harry knows how much bullying and harassment Catherine endured for nearly 10 years before she got married," she alleged. "Meghan is oblivious because she is so completely self-consumed. I think Meghan knows that she looked petty dragging Catherine during the Oprah interview and probably recognizes that she is no longer worthy of her friendship. Meghan betrayed their trust over something so insignificant."
"Meghan has no reason to fear Catherine because Catherine has a kind heart, but the Princess of Wales isn't going to give Meghan the time of day now," she claimed. "Meghan showed Catherine exactly who she is during that Oprah interview."
In August of this year, Markle told The Cut that "just by existing," she and Harry were "upsetting the dynamic of the hierarchy."
"It's interesting, I've never had to sign anything that restricts me from talking," said Markle, adding that she's "still healing."
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"I think forgiveness is really important. It takes a lot more energy to not forgive," said the 41-year-old. "But it takes a lot of effort to forgive. I've really made an active effort, especially knowing that I can say anything. I have a lot to say until I don't. Do you like that? Sometimes, as they say, the silent part is still part of the song."
Royal expert Shannon Felton Spence told Fox News Digital that "discontentment with the institution was brewing in Harry before he met Meghan."
"The dynamic of being the third wheel to William and Catherine was cute for the public, but must have been difficult for Harry," she explained. "It's very challenging to carve out your own identity within the institution, especially further down the line of succession, because the whole job is to promote the sovereign and fall behind the heir."
"What I find interesting about Katie's point is the parallel between William needing a wingman and now being all alone, and what happened to the queen, who never expected to be queen, and it changed and challenged her relation with her sister, Margaret," Felton Spence explained.
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"They were the closest of sisters," she said when referring to Queen Elizabeth II and her younger sister, Princess Margaret. "But as the queen became sovereign and stepped into that giant role, it all becomes about the job. It really challenged her relationship with her sister throughout the rest of their lives. Margaret really struggled to find her place within the institution and behind her sister."
The queen passed away on Sept. 8 at Balmoral Castle in Scotland. She was 96. The Sussexes were on a planned trip to Europe for a series of charity events when the monarch died. The couple stayed in the U.K. through Monday for Elizabeth's state funeral before her private burial. They participated in several outings honoring the late monarch, leading up to the funeral proceedings. At one point, William, 40, invited his brother and sister-in-law to join him and his wife, 40, to greet well-wishers.
In his first televised address to the nation as king, Charles said: "I want also to express my love for Harry and Meghan as they continue to build their lives overseas," which sparked hope of a reconciliation.
On Wednesday, it was reported that the Sussexes had returned to California, where they reside with their two children.
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A Buckingham Palace spokesperson didn't immediately respond to Fox News Digital's request for comment concerning Nicholl's book. However, a spokesperson previously told Fox News Digital that the palace doesn't generally comment "on such books."
In 2019, Nicholl participated in the TLC documentary "Kate v. Meghan: Princesses at War?" which aimed to examine whether there is any truth to the speculation of unrest following Markle becoming part of the British royal family.
In the special, Nicholl claimed that William was increasingly worried about his brother and his whirlwind romance with Markle following their engagement in late 2018.
"William was quite concerned that the relationship had moved so quickly," Nicholl claimed at the time. "And being close to Harry, you know, probably the only person close enough to say to Harry, 'This seems to be moving quickly. Are you sure?' And I think what was meant as well-intended brotherly advice just riled Harry."
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"Harry is hugely protective of Meghan," continued Nicholl. "He saw that as criticism, he interpreted that as his brother not really being behind this marriage, this union. And I don't think things have been quite right ever since."