“Finding Freedom: Harry, Meghan and the Making of a Modern Royal Family,” which is being serialized by the Times of London starting this weekend, said the palace “establishment’’ lived in fear of the couple’s international popularity.

The pair “might eclipse that of the royal family itself,’’ complained royal courtiers — the so-called “Men in Gray Suits” — and so worked to thwart the couple, the book said, adding that a pal of the pair referred to the Palace old guard as “the vipers.”

The anti-Meghan and -Harry resentment filtered up to the highest levels, with Kate Middleton herself refusing to even look at her sister-in-law when the women were together for their final public engagement in March, after not having seen each other since January, the book said.

Furthering the pre-Megxit tensions, Meghan and Harry kept being told they had to take a back seat to projects put forth by his dad or brother William, pals told the biographers, longtime royal watchers Omid Scobie and Carolyn Durand.

“There were just a handful of people at the palace they could trust’’ amid “the vipers,” the writers said of the young royal pair.

When the couple flew back to Britain a final time, they thought about going straight from the terminal to see Queen Elizabeth and argue their case but decided against it in the end because it would “ruffle feathers,” the book said.

The Duke and Duchess of Sussex have formally insisted they did not contribute to the chandelier-rattling biography.

Still, it was written by two journalists who reportedly are sympathetic to the couple.

The authors, are widely known in royal circles to be the Duke and Duchess of Sussex’s “cheerleaders.”

Sources told The Mail that after realizing the book would be an unstoppable in-depth “hagiography,” the couple decided to secretly use it to “settle scores” with the Royal Family.

“It’s going to be the gospel according to Meghan and Harry, so to speak,” when it comes to their engagement, marriage and Megxit, one source told The Mail.

The book, which promises a behind-the-headlines look at the couple, is due out Aug. 11, according to Amazon.

The couple issued a statement earlier Friday through their “Sussex Media Team” saying that they were not interviewed and did not contribute to “Finding Freedom.”

Still, as The Post’s Maureen Callahan recently noted, co-author Scobie told the press this past spring that he’d been working on the book with both Markle and Harry since 2018, the year they married.

The Mail reported in April that the couple gave an interview with the authors before decamping to North America.