King Charles Shields Princess Kate Amid Cancer Battle

King Charles III is fiercely protective of his daughter-in-law, Kate Middleton, as she battles an undisclosed form of cancer. The monarch has reportedly remained silent in the past about critics of Middleton's royal involvement, but now allows no criticism of her.

King Charles III is fiercely protective of his daughter-in-law, Kate Middleton, as she battles an undisclosed form of cancer.

Christopher Andersen, author of "The King," told Fox News Digital that the British monarch has been devoted to providing support for the Princess of Wales behind palace doors.

Middleton announced she had been diagnosed with cancer in March, but has kept a low profile as she undergoes chemotherapy. A spokesperson for Kensington Palace previously confirmed to Fox News Digital that the mother of three will return to official duties when "she is cleared to do so by her medical team."

"There are those inside and outside the palace who have criticized Kate over the years [before her diagnosis] for supposedly not shouldering her share of the royal burden, for not going to as many ribbon cuttings, hospital openings and plaque unveilings as the late Queen Elizabeth II, the king or Princess Anne, for instance," Andersen explained.

"It has always been Kate's choice to prioritize her children's well-being over royal duties," he shared. "In the past, Charles has remained silent about this and allowed the sniping from the sidelines to continue. But no more. Now the king brooks no criticism of Kate, period."

"Other royal family members and courtiers alike know that they risk being read the Riot Act by the king if they dare utter a negative syllable about Kate," Andersen alleged. "Charles has also made it clear that everyone should stand down in terms of when and how she returns to a full public schedule."

In February, Buckingham Palace announced that Charles had been diagnosed with a form of cancer and was undergoing treatment. A "separate issue of concern" was identified during the monarch's "benign prostate enlargement" procedure at the London Clinic.

"Subsequent diagnostic tests have identified a form of cancer," the palace said in a statement at the time.

Andersen alleged that Charles was privately impacted by Middleton's illness.

"Charles was moved to tears by Kate's stunning video announcement that she has cancer," Andersen alleged. "The king sees her as, in a word, brave. He also knows better than anyone that the future of the monarchy is to a considerable extent in her hands. She is not only the wife of a future king but the mother of a future monarch. Kate has also shown herself to be unswervingly loyal to the royal family and above reproach - things he can't always say about other Windsors."

Andersen said Charles showed his appreciation for Middleton's courage by bestowing upon her the Order of the Companions of Honour, making her the first royal ever appointed to the honor.

In her speech, Middleton assured the public that she looks forward to returning to royal duties when she is ready.

"My work has always brought me a deep sense of joy, and I look forward to being back when I am able. But for now, I must focus on making a full recovery," the princess said at the time.

"He may be chomping at the bit to resume his duties, but the king understands that Kate may take a little more time or a lot," Andersen added.

Kinsey Schofield, host of the "To Di For Daily" podcast, told Fox News Digital that the king is protective of both of "his girls" - the Princess of Wales and his wife.

"Catherine, the Princess of Wales, is what he considers the daughter he never had," said Schofield. "Catherine has been such an important part of the family for decades now. She is hard-working, focused, loving, and respected for her contributions all over the world."

Schofield cited Charles' timing of his prostate surgery announcement as an example of his protectiveness towards Middleton.

"The palace wanted to take the heat off the Princess of Wales who had just announced a planned abdominal surgery," Schofield explained. "After Catherine revealed her cancer scare ... the king was the first to publicly support her. … When King Charles gave Catherine, Princess of Wales, the title ‘Royal Companion of The Order of the Companions of Honour,’ that marked a first in British royal family history."

Charles has a long-standing fondness for Middleton. During his state visit to Kenya in 2023, the monarch recalled how Prince William proposed to Middleton at the country in 2010. He called her "my beloved daughter-in-law" at his address.

"He's always had a very good bond with her," author Sally Bedell Smith previously told People magazine. "She's interested in artistic things, and she appreciates art and culture, so [she] has an affinity with the king over that."

Smith, who penned "George VI and Elizabeth: The Marriage That Saved the Monarchy," said the king and princess now have another shared bond over their cancer diagnosis.

"Obviously, they have this in common and can only bring them closer," she noted. "It is a source of reassurance and consolation for both of them."