Queen Elizabeth II was "exhausted by the turmoil" of Prince Harry and Meghan Markle quitting royal life and told a friend "I don't care, and I don't want to think about it anymore," according to a new book.

The Duke and Duchess of Sussex's decision to leave Britain for a new life in America dominated royal reporting during the final years of Elizabeth's life.

The upcoming biography The New Royals, by Vanity Fair royal correspondent Katie Nicholl, says the saga ultimately left the queen "exhausted."

"The queen made it clear that if Harry and Meghan chose to leave, they could not reap the benefits of being royal," an excerpt from the book published in Vanity Fair said.

"And according to a friend, privately the queen confided that she was exhausted by the turmoil of their decision.

"'She was very hurt and told me, 'I don't know, I don't care, and I don't want to think about it anymore,' says that person," the excerpt continued.

"But it was a source of sadness to the queen that she got to see so little of Archie and Lilibet and that Harry and Meghan were not able to join her for a weekend at Balmoral in August, when the queen used to host a 'sleepover' for all of her grandchildren and great-grandchildren."

Meghan Markle and Prince Harry leave St. Paul's Cathedral after a service honoring Queen Elizabeth II during her Platinum Jubilee on June 3, 2022. A new biography suggests the queen felt hurt by Harry and Meghan's royal exit.Neil Mockford/GC Images

Elizabeth spent each summer in her Scottish highland estate staying there from August through September and it was there that she passed away, after a sharp decline in her health, on September 8, 2022.

Prince Harry's own description of his relationship with the queen to NBC in April 2022 struck a different tone than the one given by the friend of the queen: "We have a really special relationship, we talk about things she can't talk about with anyone else."

The book also described how King Charles III and Prince William had also felt hurt, with William struggling to forgive Harry.

"He always expected Harry would be his wingman; there was a long-term plan in place for the brothers to work together and support one another," Nicholl wrote. "After Harry announced their departure, William summoned aides to address the future, in what has been referred to by some in William's circle as the 'Anmer Summit.'

"But William and Kate also felt a sense of relief, that 'the drama was gone' when Harry and Meghan left, as a source told me. To this day, William still cannot forgive his brother.

"The brothers' estrangement also threatens to cast a shadow over Charles's reign and possibly William's. Charles knows his public reputation could suffer if he is seen to be turning his back on his youngest son."

The extract was printed by Vanity Fair on September 20, the day after Elizabeth's funeral when the royals came together and put those past differences to one side.

However, there was little sign publicly that the deep-seated problems that gave rise to the rift to begin with had been resolved.

Charles has, on multiple occasions, offered olive branches to Harry and Meghan, including when he praised his son's work on climate change in a cover essay for Newsweek in January and most recently during his first broadcast as king.

On September 9, he said: "I want also to express my love for Harry and Meghan as they continue to build their life overseas."

The queen also showed warmth to the Sussexes in her response to their bombshell Oprah Winfrey interview: "Harry, Meghan and Archie will always be much-loved family members," she said.

Harry and Meghan joined William and Kate Middleton for a joint walkabout on September 10, two days after the queen died.

There was, however, little conversation between the couples and it is at best unclear whether any resolution has been found for the deep-seated issues between them.

At worst, Harry and Meghan may come away with a batch of new resentments following a period in which there was tension over uniforms, a reception for world leaders and Harry's solo journey to Scotland in the queen's final hours.