The door may not be fully closed on Prince Harry’s return into the royal fold, according to a royal expert.

After quitting royal life and moving to the US, the Duke and Duchess of Sussex went on to launch several attacks on Harry’s estranged relatives, causing a major rift between both camps.

Soon after settling down in Montecito, Calif., the duo signed on the dotted line for a series of tell-all projects, each of which revealed bombshell details about life in the palace.

Former royal butler Grant Harrold believes there’s one thing Prince Harry could do to win his old life back.Getty Images for Project Healthy Minds

After sitting down for an interview with Oprah Winfrey, the Sussexes went on to release their six-part Netflix documentary, as well as Harry’s protocol-shattering memoir, “Spare.”

And while hopes of a reconciliation may be slim at this time, King Charles’ former royal butler Grant Harrold believes there’s one thing Harry could do to win his old life back.

“The only way I see this happening is a public statement from Harry, where you come out and say that you were in a bad space and that [Spare] was a mistake,” Harrold exclusively told The Post.

“I don’t think that’s going to happen. Some bad things were said, and some families never patch things up, and that’s how it is forevermore,” he said, adding that Harry “will regret” the things he wrote in his book.

The Duke and Duchess of Sussex quit royal life in 2020 and moved to the US.Getty Images for the Invictus Games Foundation

“Harry has got a big heart, and a part of him probably wishes things would be different,” Harrold added.

Last month, the Sussexes were urged to stop “monetizing” their links to the Windsor clan if they ever want to be welcomed back into the royal family — at any capacity.

Still, while there is a chance for Harry to be let back into the royal fold, Harrold says he and his wife, Meghan Markle, will never get back the relationship they once had with the Prince and Princess of Wales.

A public apology from Harry could be the thing that finally mends the rift between both camps, Harrold claims.Mirrorpix / MEGA

“[Harry] caused damage and broke down trust,” Harrold exclusively told The Post. “It’s difficult when you’re a future monarch.”

“I doubt they’ll ever get back the relationship they had originally. That was a very different relationship built on trust,” he said, adding that “too much damage” has already been done. “It’s going to take time. William is a tough character. He’s a good guy.”