King Charles and Queen Camilla's New Bust-Up — After Queen 'Pushed Monarch Not to See Estranged Son Harry on US Tour'

It's yet another missed connection for Prince Harry and his father, King Charles III, RadarOnline.com can reveal.

Back in January, Harry left the U.K. after a brief trip to give evidence in his court case against a British newspaper without seeing his ailing father – who is battling cancer – and in late March, it was reported that the 77-year-old monarch wouldn't be able to slot in any face time with his son during his four-day state visit to the United States to commemorate the 250th anniversary of American independence in late April.

"Harry understands that Charles' trip was scheduled way in advance and that his calendar will be jam-packed," a source told RadarOnline.com. "But he's still extremely disappointed he couldn't have been squeezed in somehow. It would've meant the world to him."

Charles' U.S. itinerary will indeed be hectic. He and wife, Queen Camilla, are set to attend a state dinner with President Donald Trump on April 28, and will meet with families of 9/11 victims in New York City and make appearances in Virginia as well.

But the source told RadarOnline.com the real reason Charles won't meet with his 41-year-old younger son has nothing to do with his busy docket – instead, it's because Camilla is doing "all she can" to keep the two men apart.

"Camilla did not want the meeting to happen," said the source. "She thinks Harry has caused untold trouble for his father and the royal family, and she has no interest in patching things up."

"Charles feels he has no choice but to go along with Camilla," the source added, "because doing otherwise would cause too much tension at home."

Camilla's resentment of Harry goes back to 2020, when the prince and his American-born wife, Meghan Markle, 44, left the royal family and made a new life for themselves as the Duke and Duchess of Sussex in Montecito, Calif. – including giving royals-bashing interviews and selling his memoir, Spare, and a tell-all docuseries.

"Camilla hates that Harry and Meghan are still shamelessly cashing in on their royal titles," the source explained.

The couple was most recently under fire for posing their mid-April trip to Australia as a quasi-royal tour, with critics pointing out that they made money from paid speaking events –Harry was a keynote speaker at the InterEdge Summit on April 16; Markle headlined a weekend retreat for which tickets started at $1,930.

"Camilla thinks Harry is a treacherous, selfish wretch," the source said.

The feelings go both ways.

"Harry still views Camilla as his father's mistress who broke up his parents' marriage," added the source.

In 2023's Spare Harry admitted he was against Charles' marriage to Camilla, who waged a canny PR war to rebuild her reputation after Harry's late mom, Princess] Diana's infamous revelation that there were "three of us in this marriage."

Harry implied in an interview with 60 Minutes that Camilla traded favors with U.K. papers by offering negative stories about him in exchange for positive ones about her.

"Harry finds Camilla loathsome and unbearably bossy and entitled," the source said.

Harry's anger has only intensified over Camilla's treatment of Markle. In his new book, Betrayal: Power, Deceit and the Fight for the Future of the Royal Family, Tom Bower writes that Camilla allegedly told a friend that the former Suits star had "brainwashed Harry."

Harry and Markle slammed Bower's book in a statement saying he's peddling "deranged conspiracy and melodrama."

The source said: "Harry believes Camilla has no business judging Meghan after all the anguish she herself caused the royals."

Charles is caught in the middle.

"He doesn't discount Camilla's complaints, but Harry is his son and he feels like she should understand why he wants to have a relationship with him and his grandchildren," revealed the source, noting that the king was up for seeing Harry, but "it became impossible because Camilla put her foot down, and Charles doesn't have the energy to go up against her."

In December, the monarch revealed he was responding well to – and therefore scaling back on – his cancer treatment.