Prince Harry and Prince William

Ahead of the debut of Prince Harry‘s highly anticipated memoir, Spare, an excerpt revealing a chilling run-in the duke had with his brother, Prince William, has been released.

In the book, Harry describes that one day in 2019, he and William had a heated fight about Duchess Meghan, whom the Duke of Sussex had married a year earlier.

He writes that William came to his home, Nottingham Cottage at Kensington Palace, wanting to talk about their relationship and struggles with the U.K. media, but when he got there, the future king was already “piping hot,” per an excerpt obtained by The Guardian.

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Harry says William called Meghan “difficult,” “rude,” and “abrasive.” Harry told his brother he was just repeating the press narrative about her, but William, Harry says, was thinking like an heir, rather than a brother, and refused to be rational.

Insults were exchanged, Harry writes, and William claimed he was trying to help.

“Are you serious? Help me? Sorry—is that what you call this? Helping me?” Harry recalls telling his brother.

That comment angered William, Harry says, and caused him to insult and lunge at Harry inside his home.

Harry says he gave his brother a glass of water and said, “Willy, I can’t speak to you when you’re like this.”

“He set down the water, called me another name, then came at me. It all happened so fast. So very fast. 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,” Harry writes. “I lay there for a moment, dazed, then got to my feet and told him to get out.”

Harry writes that William urged him to hit back, but Harry refused, so William left.

William then returned “looking regretful, and apologised,” per Harry, and said, “You don’t need to tell Meg about this.”

“You mean that you attacked me?” Harry says he asked him.

“I didn’t attack you, Harold,” William replied.

Harry writes that he called his therapist to talk about the altercation and eventually did tell Meghan, after she noticed the “scrapes and bruises” he had on his back.

He says she “wasn’t that surprised, and wasn’t all that angry.” Instead, “she was terribly sad.”

Spare will be released on January 10.

This article originally appeared in Harper’s BAZAAR US.