Prince Harry was left off the guest list for cousin Peter Phillips’ upcoming wedding to Harriet Sperling because the groom’s loyalties allegedly lie with Prince William.

Royal commentator Emily Nash exclusively spoke with Page Six while promoting her upcoming appearance on the live recording of Hello! Magazine’s “A Right Royal Podcast” next Tuesday.

“I think it comes down to interpersonal relationships, doesn’t it?” Nash said. “What we were told was that Peter hadn’t spoken to Harry for the last few years. And so it sort of has been a natural cooling off and he wasn’t invited as a result.”

Nash explained that Phillips is, however, “very close” to the Prince of Wales.

“[Peter is] very loyal; he’s very protective. He’s been a very good sounding board to his cousin over the years,” Nash said. “So it absolutely makes sense that I think had both Wales brothers been there, it would have put a completely different slant on the whole event.”

“And that’s not what you want on what should be the happiest day of your life, right?” she added.

Page Six has reached out to representatives for Prince Harry but didn’t immediately get a response.

Nash recalled Phillips, 48, being the “peacemaker” between the Duke of Sussex, 41, and his older brother, 43, during Prince Philip’s 2021 funeral.

“Peter was positioned between the two warring brothers,” Nash said. “He was sort of put right in the middle of them as the older cousin, and that must have been a really difficult moment for him.”

She added, “Of course, a lot of water has gone under the bridge since then.”

Nash cited Harry’s tell-all memoir “Spare” and his and wife Meghan Markle’s Netflix docuseries — both of which laid bare the family’s private tensions — as more reasons for his falling out with Princess Anne’s son.

The Hello! Magazine editor believes it was a “smart” move that Harry was snubbed from the wedding.

“If that had been the case, that would have become the absolute focal point for Peter and Harriet’s special day, and there have been enough distractions, I think, from the good things about the royal family over the past year,” Nash said. “Hopefully, they can just have this one day to come together and celebrate someone’s happy news for a change.”

William and wife Kate Middleton are expected to attend the June 6 nuptials, and Nash believes King Charles III will also “make an appearance.”

She also expects that the Prince and Princess of Wales’ kids could attend, and Phillips’ sister, Zara Tindall, and her husband, Mike, are a definite yes.

Harriet’s daughter from her first marriage to Antonio St. John Sperling, Georgina, is expected to attend as well.

“There is a real family at the heart of it — and a blended one as well. So it really is reflecting the much more modern face of the royal family,” Nash said.

Princess Eugenie and Princess Beatrice are also expected to attend, marking their first major appearance with their royal family members since their dad, former Prince Andrew, was arrested over his ties to Jeffrey Epstein.

“It will kind of show that there is still a place for them within the family,” Nash said of their attendance at the ceremony, before warning, “But it’s also important to remember this is very much a family occasion
and not an official one.”

“So you can’t read too much into these things, but I think it’s going to be fascinating to see how they interact with other members of the family,” she said.

As for the chances that Eugenie and Beatrice’s mom, Sarah Ferguson, will attend, Nash said, “I would say slim to zero.”

“I don’t think we’ll see either Andrew or Sarah there,” she said. “The last year has been catastrophic for them as individuals and as a former couple.”