Prince Harry reportedly alleges in new book that brother William physically attacked him

LONDON — Prince Harry's upcoming autobiography details an alleged fight in which his older brother, the future British king Prince William, pushed him to the floor, according to a report in The Guardian newspaper on Thursday.

The U.K. newspaper cited a copy of the book, titled "Spare," which it says it obtained ahead of its publication on Jan. 10. CNBC or NBC News have not seen or been able to obtain a copy of the book.

Harry described in a recent Netflix documentary how his relationship with his brother William, currently the Prince of Wales and first in line to the throne, deteriorated amid negative media coverage of his wife Meghan Markle and the couple's decision to walk away from their roles as senior members of the royal family.

Harry and Meghan remain the Duke and Duchess of Sussex but gave up the title "royal highness" and no longer receive public funds.

In "Spare," Harry will claim that during a 2019 fight at his home in London, William called Meghan "difficult," "rude" and "abrasive," according to the Guardian report. Harry reportedly accuses him of repeating attack lines in the British press.

Harry also alleges William grabbed him by the collar, ripping his necklace, and knocked him to the floor. He writes he then landed on a dog bowl which shattered, leaving him with "scrapes and bruises."

Kensington Palace, representing the Prince of Wales, and Buckingham Palace, representing King Charles III, have declined to comment on the allegations. A representative for Prince Harry declined to comment on the record to NBC News and "Spare" publisher Penguin Random House has not yet responded to an NBC News request for comment.

"Spare" is expected to contain a host of new accounts of conversations that have taken place between senior royals and their actions, including their relationship with the U.K. press, which Harry has heavily criticized.

Its publication follows a series of media appearances by Harry and Meghan, who married in 2018 and stepped down as senior royals in early 2020.

In March 2021, they were interviewed by Oprah and made a series of claims about the behavior of the royal family, including that one member had "concerns and conversations" about how dark the color of Harry and Meghan's first child would be. Meghan is biracial.

She also alleged she had been the victim of a "character assassination" by the British press and was not defended by the palace, with the pressure leaving her feeling she "didn't want to be alive anymore."

William denied that the family were racist in public comments at the time, and the palace said in a statement that the allegations were "concerning" and that "while some recollections may vary, they are taken very seriously and will be addressed by the family privately."

In a six-part documentary released in December, the couple further criticized the media and detailed strained relationships with royal family members, as well as the story of their relationship and move to the U.S. They currently live in Santa Barbara, California.

"Harry & Meghan," directed by Oscar-nominated Liz Garbus, was Netflix's biggest-ever debut documentary and notched 81.55 million views within its first four days of release, according to the streaming service.

Since resigning as senior royals, Harry and Meghan have said they will be financially independent, though Harry has strongly criticized a U.K. government decision to withdraw taxpayer-funded police protection for his family in 2020.

"Spare," published by Penguin Random House, will be released in audiobook and hardback next week and is currently among the top preselling books on the U.K. and U.S. Amazon websites. A publisher bio says proceeds from the book will go to charities, with $1.5 million already paid to Sentebale, a charity supporting young people in Lesotho and Botswana affected by HIV and AIDS.

The couple have also signed a multi-year deal with Spotify through their production house Archewell, reported to have been worth between $20 million to $30 million, with Meghan launching an interview podcast in 2022.

Archewell Productions is due to release another Netflix series, "Heart of Invictus," in 2023.

If you are having suicidal thoughts, contact the Suicide & Crisis Lifeline in the U.S. at 988 or the Samaritans in the U.K. at 116 123.