Santa Barbara, California - Prince Harry's highly anticipated autobiography will reportedly contain the bombshell claim that he was physically attacked by his brother William over the Duke of Sussex's marriage to Meghan Markle!

In an extract of his book, Spare, leaked to the Guardian newspaper, Prince Harry alleged the confrontation took place at his London home in 2019 and had left him with a visible injury to his back, as William grabbed him by the collar and ripped his necklace before knocking him to the floor.

Harry also claimed the Prince of Wales had called the American actor "difficult," "rude," and "abrasive" – comments which the younger brother said parroted "the press narrative" about his wife.

According to the Guardian, the "extraordinary scene" is "one of many in Spare" which is due to be published on January 10.

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The outlet said it was able to obtain a copy of the book despite "stringent pre-launch security around the book."

The article goes on to say that, according to Harry, his elder brother had wanted to discuss "the whole rolling catastrophe" of their relationship and struggles with the press.

But when William arrived at Nottingham Cottage, where Harry was then living, he was already "piping hot."

"After William complained about Meghan, Harry writes, Harry told him he was repeating the press narrative and that he expected better," the Guardian reported.

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As the conversation devolved into shouting, insults were exchanged between the two men and things got physical.

"(William) called me another name, then came at me. It all happened so fast. So very fast," Harry wrote. "He grabbed me by the collar, ripping my necklace, and he knocked me to the floor. I landed on the dog’s bowl, which cracked under my back, the pieces cutting into me. I lay there for a moment, dazed, then got to my feet and told him to get out."

The Duke of Sussex also claimed that William urged him to hit back, but he refused.

Ultimately, William apologized and asked him not to tell Meghan about the confrontation. Harry said he did not immediately tell his wife but she ended up noticing "scrapes and bruises" on his back.

Earlier in the memoir, Harry reportedly reveals the meaning of the book’s title. Per the Guardian, he recounts what his father, now King Charles, said to Diana, Princess of Wales on the day of his birth: "Wonderful! Now you’ve given me an heir and a spare – my work is done."

The duke’s extraordinary book claims come after the release of a teaser trailer from an interview with British TV channel ITV, in which Harry said he wants his father and brother back.

The interview, due to be released on Sunday, will be broadcast two days before Spare is published around the world.