Prince William refused to eat with Prince Harry at a summit to discuss Megxit, a new book claims.
The Duke of Sussex was left to dine alone with Queen Elizabeth II, according to Robert Lacey's new book Battle of Brothers.
William was reportedly distraught after Harry and Meghan announced they wanted to step down as senior members of the Royal Family with a statement on social media.
The Duke of Cambridge is said to have thought Harry had "betrayed" the Queen by announcing Megxit plans without consulting her.
After the announcement, made by the Duke and Duchess of Sussex on social media without warning other members of the Royal Family, a summit was organised in Sandringham for senior royals to discuss the couple's plans.
But even though the monarch invited the family to have lunch together before the meeting, Prince William did not dine with them and only said he wanted to attend the summit, according to the book.
The royal author wrote: "The Queen had suggested the family should gather for lunch before their big pow-wow in the library that afternoon, but he refused his grandmother’s invitation.
"He would obviously turn up at 2pm for the meeting, he said, but he only wanted to talk business.
"The Prince himself has not confirmed his friends’ speculation that he was so furious with his younger brother that he would not be able to endure the hypocrisy of smiling at him over lunch."
Following the summit, a statement from the Queen said they had “constructive discussions on the future of my grandson and his family”.
It added: “My family and I are entirely supportive of their desire to create a new life.
“Although we would have preferred them to remain full-time working members of the Royal Family, we respect and understand their wish to live a more independent life while remaining a valued part of my family.”
According to insiders, that was one of the last times William and Harry spoke.
A source said of the Megxit rift: “Harry hadn’t even had a meeting with the Queen to talk through their plans before announcing it to the world.
"The monarchy is an institution based on hierarchy and respect - something drummed into those boys growing up."
William was reportedly hurt by the decision because he "loves his brother deeply", according to The Sun.
The book also claims the rift between the two brothers "could cause immense damage to the monarchy".
Among other claims, the author wrote the two brothers did not speak much after Harry and Meghan moved to North America, other than wishing each other Happy Birthday.