A Kingdom in Transition: Ailing King Charles' Power Fades as Prince William and Kate Middleton 'Quietly' Gain Control Behind the Scenes

His Majesty King Charles III's two-year-old reign is reportedly not shaping up to be like he expected, especially considering he was the longest-waiting heir in British history.

In fact, as the monarch still battles cancer, "executive power and influence is already flowing William's way," royal reporter Tom Sykes wrote for The Daily Beast.

One shift in this direction was reported to be Catherine, Princess of Wales' "cinematic" video in early September detailing the end of her chemotherapy treatments. Sykes shared how the video allegedly was not first approved by the King, which would have been unthinkable during Queen Elizabeth II's reign.

He added, "To get away with such cheek showed William and Kate have an instinctive understanding... of how the power dynamic has shifted since the king’s diagnosis."

The King, 75, along with Queen Camilla, 77, is set to undertake an 11-day tour of Australia and Somoa starting Friday, October 18, but his absence from public-facing duties in Britain since the end of his annual summer-long Balmoral vacation has ignited speculation that his battle with the disease is stirring rumors that he is a "weak" King.

"The fortnight in the run-up to the royal tour has been kept deliberately light for His Majesty," a source told a publication. "He will still be undertaking meetings, doing his paperwork and still come down for treatment. Australia is a big deal and he wants to be fighting fit."

With His Majesty conserving all his energy for his first tour of a Commonwealth realm since inheriting the Crown, it's next holder and his future consort "are definitely proving to be the stars of the show."

"In the latter decades of the late Queen's reign, you had Diana, Fergie, Kate and Meghan, pop up and steal the limelight for a time — but Elizabeth's hold over the public's imagination never once faltered," a palace insider spilled. "The same cannot be said for Charles because fate played a cruel trick on him."

They added, "William and Kate are a force to be reckoned with."

It's a classic royal story in the British monarchy that the heir outshines the monarch. For Charles III, many see William and Kate as the true stars.

"You have to feel sorry for Charles: Being snubbed by his son and heir who is off making the most of a 'shifting power dynamic' while he valiantly battles on, through cancer, to try and keep his mother’s legacy going for a bit longer," royal expert Daniela Elser wrote.

She concluded, "That an 11-day trip, undertaken to the highest degree of luxury and comfort, requires weeks of conserving his energy doesn’t just tell us a story about a man facing down a serious illness, but about a king trying so very hard to hold things together."

Prince William will become the monarch upon his father's death.