Prince Harry and his wife Meghan Markle are returning to the U.K. for a series of charity events — and one royal author suspects that Prince William and Kate Middleton will avoid them.

In August, a spokesperson for the Duke and Duchess of Sussex announced that they "are delighted to visit with several charities close to their hearts in early September."

The couple will travel to Manchester, England, for the One Young World Summit on Sept. 5, Germany for the Invictus Games' "One Year to Go" on Sept. 6, and then London for the Well Child Awards on Sept. 8. The pair were last in the U.K. in June for Queen Elizabeth’s Platinum Jubilee.

It is unknown whether they will visit the monarch, 96, who has been residing at Balmoral Castle in Scotland. Author Christopher Andersen said it’s unlikely that the pair will meet with the Duke and Duchess of Cambridge.

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Prince William Prince Harry Meghan Markle Kate Middleton

Author Christopher Andersen alleged that the relationship between the Sussexes and Cambridges continues to be strained. (Phil Harris - WPA Pool/Getty Images)

"It’s going to be interesting in the next few days when Harry and Megan go to Europe, and they’re gonna be playing royal hide and seek," Andersen recently told US Weekly.

Anderson, who wrote a new book titled "The Day Diana Died," pointed out that the Cambridges are currently in Scotland with the queen, Prince Charles and Camilla, Duchess of Cornwall. They will return while the Sussexes are in the U.K.

"They’re out of the way during the first part of the Sussexes trip to Britain, but on [Sept. 8], the Sussexes return to Britain from Germany," Andersen explained to the outlet. "They’re going to be, literally, a brief stroll from each other on the grounds of Windsor because the Cambridges have to [return in time to get their] kids in school."

While the Sussexes have relocated to California, they’ve kept Frogmore Cottage as their U.K. home. 

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The Sussexes reside in California, but they have kept Frogmore Cottage as their U.K. home. (Patrick van Katwijk/Getty Images)

"It’s gonna have all the markings of an old-fashioned farce with these people trying to avoid each other," Anderson alleged to the outlet.

In late 2021, Andersen told Fox News Digital that Harry’s relationship with his older brother has been strained.

"There’s a lot of bad blood between them now," Andersen alleged at the time. "It’s really Charles and William versus Harry and Meghan. William is fiercely loyal to his father. He thinks his father is a great historical figure who has been underestimated. And he feels for his dad. They all love the queen, but when you’re maybe going to be king when you’re almost 80 years old, it’s a sad position to be in. So William has been by his father’s side."

"After Prince Philip’s funeral [in 2021], they set up a meeting with the three of them — Harry, William and Charles — with nobody else around," Andersen claimed. "It did not go well. The next day, Harry got on a plane and left. For the unveiling of the Diana statue [that same year], a similar thing happened [with William]. Even though they were grinning from ear to ear, they were walking with their backs to each other."

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Queen Elizabeth II attends the beacon lighting

Queen Elizabeth II, 96, has been in Balmoral Castle amid ongoing mobility issues. (Steve Parsons-Pool)

In response, a spokesperson for Buckingham Palace told Fox News Digital that "we never comment on these sort of books." A spokesperson for Kensington Palace, which represents the household of the Duke and Duchess of Cambridge, had "no comment." A spokesperson for Clarence House, which represents Charles and Camilla’s household, didn’t immediately respond to Fox News Digital's request for comment. However, a spokesperson told The New York Post that "this is fiction and not worth further comment." A spokesperson for the Duke and Duchess and Sussex also didn’t immediately respond to Fox News Digital's request for comment.

Andersen said he was sticking by his claims.

"I have sources that I’ve been tending to for 50 years," said Andersen, who has previously written several books on the royal family.

Markle, a former American actress, became the Duchess of Sussex when she married the British prince in May 2018 at Windsor Castle. The couple welcomed a son named Archie Harrison Mountbatten-Windsor in 2019.

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Meghan Markle for Spotify

While the Sussexes are traveling across the pond, Meghan Markle's podcast "Archetypes" will release a new episode on Tuesday. (Spotify)

The Duke and Duchess of Sussex’s departures from royal duties began in 2020 over what they described as the British media’s intrusions and racist attitudes towards the former "Suits" star Markle, 41. The family now resides in the coastal city of Montecito, California.

In the wake of quitting royal duties, they gave an explosive TV interview to Oprah Winfrey in March 2021, in which the couple described painful comments about how dark Archie’s skin might be before his birth. The duchess talked about the intense isolation she felt inside the royal family that led her to contemplate suicide.

Buckingham Palace said the allegations of racism made by the couple were "concerning" and would be addressed privately.

In June of that year, the couple welcomed their second child, a daughter named Lilibet "Lili" Diana Mountbatten-Windsor. The name pays tribute to both Harry’s grandmother, whose family nickname is Lilibet, and his late mother, Princess Diana.

The Associated Press contributed to this report.