Royal author Omid Scobie, a close ally of Prince Harry and Meghan Markle, has claimed Prince William's staff planted stories about his brother's mental health in the media.
Scobie co-wrote the 2020 book Finding Freedom, a biography of Harry and Meghan which explored their split from the rest of the royal family and detailed their side of the story.
He has been interviewed for a new documentary on the British television channel ITV called: Harry and William: What Went Wrong?
Among other things, the program delves into allegations that "many of the negative stories about Harry and Meghan" in the British media were "the result of briefings from within the Palace".
Scobie's quotes concern the aftermath of Harry and Meghan's interview with ITV's Tom Bradby in 2019, towards the end of their tour of South Africa.
That was the interview in which Meghan first alluded to her mental health struggles in public, saying: "Not many people have asked me if I'm OK."
It also included an admission from Harry that he'd drifted apart from William.
"We are certainly on different paths at the moment, but I will always be there for him, as I know he will always be there for me," the Duke of Sussex said.
"We don't see each other as much as we used to, but I love him dearly, and the majority of stuff is created out of nothing. As brothers, you have good days, you have bad days."
Shortly after the interview, the BBC reported William was "worried" about his brother, citing a Kensington Palace source, who added that the royals felt Harry and Meghan were "in a fragile place".
A different source claimed William was "furious" with Harry for giving the interview.
"I would say that it was no coincidence that it was shortly after that aired, even the next day, there were source quotes that came from a senior aide at Kensington Palace saying that William was worried about his brother's mental health," Scobie tells the ITV documentary, referring to those anonymous quotes.
"That fed off such an ugly thing for Harry and it did not go unnoticed. Now, whether William directed that or not, no one will ever know, but it came from his household that he is the boss of."
Scobie does not provide any evidence that William directed the leak.
EMOTIONAL ADMISSION: Meghan, Duchess of Sussex, is speaking out for the first time about the public pressure she faced as a new Royal and new mom, telling ITV News anchor Tom Bradby “not many people have asked if I'm OK." @giobenitez reports. pic.twitter.com/5CyTteU5qC
— World News Tonight (@ABCWorldNews) October 19, 2019
In another moment, the royal expert defended Meghan, saying she "ruffled feathers" in the Palace because of her work ethic.
"Meghan came in driven and ready to work, and that immediately ruffled feathers. She's a woman well into her thirties. I think she's proven to herself and the people she's worked with up until that point that she knows what she's doing," said Scobie.
"She was certainly not someone who was going to change herself just to please the people around her. I felt they also had to be reminded: 'You're not the stars of the show here. There is a hierarchy and you don't come very high in it.'"
The documentary also features quotes from sources who are less friendly towards the Sussexes, such as royal biographer Penny Junor.
"I was hearing very bad stories from early on that Meghan was upsetting people. She was not as charming as she seemed," says Junor.
"Harry and Meghan's approach is not just Californian, it's showbizy, celebrity. Our royal family are not celebrities. They are working members of a public institution.
"I was appalled by the Oprah interview. These are not statements that should be made for public consumption. This is the sort of thing that should happen in the privacy of a psychiatrist's couch."
Harry and Meghan's interview with Oprah Winfrey earlier this year included allegations that the Palace prevented the Duchess from seeking treatment for her mental health, and that a senior royal expressed concerns about her son Archie's skin colour.
The Palace is investigating claims that Meghan mistreated her staff during her time in the United Kingdom, which the Sussexes have dismissed as a "smear campaign".
Last week Harry returned to the UK and appeared alongside William for the unveiling of a statue of their mother Diana at Kensington Palace.
It was an emotional and rare show of unity from the pair, who commissioned the statue back in 2017.
"Today, on what would have been our mother's 60th birthday, we remember her love, strength and character – qualities that made her a force for good around the world, changing countless lives for the better," they said in a joint statement.
"Every day, we wish she were still with us, and our hope is that this statue will be seen forever as a symbol of her life and her legacy."