The royal family is “hugely nervous” about Prince Harry’s memoir, a royal biographer says.

Tom Bower, who wrote “Revenge: Meghan, Harry and the War Between the Windsors,” tells Page Six in an exclusive new interview that the Duke of Sussex’s upcoming book is a “time bomb.”

We previously reported that Harry, 38, is desperate to rewrite the book in the wake of Queen Elizabeth II’s death last month, wanting to “take out or downplay” what he wrote about King Charles III, Queen Consort Camilla, Prince William and Kate Middleton.

But Bower doesn’t think that can happen.

“I think that everybody knows that the Sussexes can’t amend the book in any way,” he opines. “Can they make it nastier? Because otherwise, we wouldn’t get sales.”

Harry’s memoir, originally scheduled for release from Penguin Random House in November, has already been pushed back until sometime next year.

Bower says chatter in London has the book coming out around “Easter and will include in it a chapter on the [Queen’s] funeral.”

“And there’ll just be more material about how they were snubbed and all the rest of the invective against the royal family,” he adds. “So I think to that extent, the delay will add to the poison.”

Many royal experts have said that Charles, 73, is holding off on whether he will bestow the title of prince and princess to Harry and Markle’s children, Archie, 3, and Lilibet, 1, until the couple’s various media projects are released.

Harry and Markle, 41, have also been working on a Netflix docuseries for more than a year.

Invictus Games 2020 - Day 2
Harry and Meghan Markle are also working on a Netflix docuseries.

Page Six reported that the duke and duchess have also wanted to re-edit the series, which Netflix had hoped to air in December following the fifth season of “The Crown” on Nov. 9. Such edits “would potentially push back its release until later in 2023,” a source said.

Harry and Markle tied the knot in May 2018 and resigned from their royal duties less than two years later amid claims that the former actress and their first child faced racial bias and that she had contemplated suicide while pregnant with Archie.

They eventually moved to California and signed lucrative deals with Spotify and Netflix.