Prince Harry has referred to Prince William as his "arch-nemesis".
The 38-year-old royal admitted there has "always been" a sense of "competition" between himself and the Prince of Wales and thinks they have naturally fallen into the dynamic of the heir and the spare, an old saying refering to the fact the eldest child will inherit titles and power and a second sibling is purely there in case anything happens to the first-born.
In a preview clip for Harry's upcoming interview on 'Good Morning America', Michael Strahan asked: "There's a quote in the book where you refer to your brother as your 'beloved brother and arch-nemesis.' Strong words. What did you mean by that?"
Harry replied: "There has always been this competition between us, weirdly. I think it really plays into or always played by the 'heir/spare.'"
The preview was released hours after leaked extracts from Harry's upcoming memoir 'Spare' saw the prince - who stepped back from royal duties in 2020 to start a new life in the US with wife Meghan, Duchess of Sussex - allege his older brother, Prince William "knocked him to the floor" during an argument.
According to Harry, his sibling branded Meghan "difficult", "rude" and "abrasive", before the row escalated.
He wrote William "grabbed me by the collar, ripping my necklace, and ... knocked me to the floor".
Harry said he had given his brother a glass of water during the bust up and had said: "I can’t speak to you when you’re like this."
He added: "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. I lay there for a moment, dazed, then got to my feet and told him to get out."
Harry also claims William told him: "You don’t need to tell Meg about this," and he is said to have replied: "You mean that you attacked me?"
The duke writes that William then said: “I didn’t attack you, Harold."