King Charles Will Not Accept Criticism of His 'Beloved Daughter-in-Law' Kate Middleton: 'They Risk Being Read the Riot Act'

King Charles and Kate Middleton are currently battling cancer, and royal experts believe the king is being protective of the Princess of Wales as she juggles her health challenges and raising her three kids, Prince George, Princess Charlotte and Prince Louis.

"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," Christopher Andersen told an outlet.

"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."

Charles returned to "forward-facing duties" in late April, but Kate is still avoiding the spotlight.

"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."

On Friday, March 22, Kate surprised the world when she revealed she had cancer after months of conspiracy theories spread about her well-being.

"I wanted to take this opportunity to say thank you personally for all the wonderful messages of support and understanding whilst I've been recovering from surgery," Kate began in a video posted to Instagram. "It has been an incredibly tough couple of months for our entire family. In January, I underwent major abdominal surgery in London. At the time, it was thought that my condition was non-cancerous. The surgery was successful, however, tests after the operation found cancer had been present. My medical team therefore advised I should undergo preventive chemotherapy, and I am now in the early stages of that treatment."

Shortly after Kate updated the public on her condition, Charles said he was "so proud of Catherine for her courage in speaking as she did." Buckingham Palace later shared that His Majesty was in "closest contact with his beloved daughter-in-law."

The King and Queen Camilla "will continue to offer their love and support to the whole family through this difficult time," the palace said.

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According to the biographer, Charles was emotional after seeing Kate's social media post.

"Charles was moved to tears by Kate's stunning video announcement that she has cancer," Andersen said. "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," he continued. "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."

Although Kate embraced a more reserved lifestyle in recent months, Charles gave her a distinguished role.

"The king showed his appreciation several weeks ago by bestowing on Kate the highest accolade he could, making her the first royal ever appointed to the Order of the Companions of Honour," Andersen explained. "Nobody understands more fully than King Charles just how difficult fighting cancer can be — the toll it takes emotionally and physically."

"The king has made it clear that whatever Kate feels she needs, she gets," he added.

Andersen spoke to Fox News Digital.