Prince William and his estranged brother, Prince Harry, have endured a strained relationship since the latter left behind official royal duties.

Royal biographer Tom Bower alleges that, should Invictus Games founder Harry, 38, propose a truce to William and his wife, Kate Middleton, both 41, it could be refused.

He recently told OK! that the Duke of Sussex “can’t come back” to the Firm because he has “caused so much damage to the family.”

Harry and his wife, Meghan Markle, moved to California in 2020, since releasing a slew of projects detailing their struggles with royal life, including his memoir, “Spare,” and their Netflix doc, “Harry & Meghan.”

“I think Harry’s offer will ultimately be rejected. I doubt William and Kate can forgive Harry,” he explained.

A source had also claimed to the publication that Harry called William recently in an attempt to end their feud. However, the Prince of Wales was left “stunned” and didn’t know how to respond.

“The concern now is that if he does return, he could well damage it even further,” he went on.

He then added that the former actress “would’ve been horrified by Harry’s suggestion” of a truce as she’s “not close” to the Duke and Duchess of Cambridge.

“London was just a stepping stone for her. I would imagine the last thing she’d want to do is return to England to live in a small, poky flat in Kensington Palace,” Bowers said.

Whispers of a ceasefire were also shared by an insider who told In Touch: “Harry admitted he’d phoned William to call a truce and told his brother he and Meghan would be open to going back to London, where they would serve King Charles.”

The insider revealed that the monarch, 74, would “think about [Harry’s] offer.”

Harry and Markle have gone back to the UK just a handful of times since their royal departure.

They flew across the pond for the funeral of Queen Elizabeth in September 2022 and Harry returned to attend the coronation of Charles this past May.

Harry was even demoted to a third-row seat at the crowning at Westminster Abbey and sat with his cousin Princess Eugenie’s husband, Jack Brooksbank, and Princess Alexandra, one of the late queen’s cousins.

The front row was reserved for full-time working royals and included William, Middleton and their children, Princess Louis and Princess Charlotte.