EXCLUSIVE: Kate Middleton 'Was Crowned Queen' in 'Ultra-Secret Royal Training' Ahead of King Charles' 'Inevitable' Cancer Death

Her appearance was unexpected – and beautifully received as she embarked on secret royal training that saw her "crowned queen" in an ultra-quiet ceremony, RadarOnline.com can reveal.

An insider said: "Kate wore a crown and has been taking lessons in what it means to be queen ahead of King Charles' death, and was crowned in a hush-hush ceremony to prepare her for what's coming."

It comes after Kate has been acting like a queen in public for months.

Stepping out in an impeccably tailored olive-green Victoria Beckham pantsuit and white silk blouse for her first solo official outing this spring, Princess Kate Middleton stunned a London fashion crowd on May 13 as she presented the Queen Elizabeth II Award for British Design to 29-year-old Patrick McDowell at an event organized by the British Fashion Council.

As the Princess of Wales examined the clothes on display, McDowell said a sleeveless piece called the "Wales jacket" caught her eye.

"She said, 'Why would you call it that?' with a big smile," the winning designer shared, marveling: "What a moment, to be sharing jokes with our future queen."

The gracious appearance is just another example of the 43-year-old's tremendous power and appeal.

In recent weeks, Middleton has increased both the frequency and visibility of her public engagements following her cancer diagnosis and successful treatment last year – and it’s all down to duty.

"These are tenuous times for the monarchy," a source told Radaronline.com, with King Charles III, 76, more than a year into his own cancer battle, his heir, Prince William, 42, "under intense pressure due to his position as king-in-waiting," plus ongoing family drama with the Duke and Duchess of Sussex "still giving them grief."

As a result, the most senior royal men are "falling apart behind the scenes," added the source. As they spiral, however, "strong, resilient" Middleton has taken charge.

Her popularity also continues to outshine most royals.

According to a YouGov poll released in May, the mother of three is liked by 72 percent of Britons, edged out only by William, who is liked by 75 percent of his future subjects (next was Princess Anne, 74, with 69 percent, then Charles with 61 percent.

Duchess of Sussex Meghan Markle, with 20 percent, beat out only the disgraced Prince Andrew's five percent.)

Middleton "has always followed the rules and managed to avoid the pitfalls that plagued other royal women, like the late Princess Diana, especially when dealing with the media," our source said. "She feels it's her duty to step up and protect the crown."

More than a year after being diagnosed with an undisclosed form of cancer, Charles is still undergoing treatment.

In March, he was briefly hospitalized due to what Buckingham Palace called "temporary side effects."

The next month, His Majesty confessed his diagnosis has been "a daunting and at times frightening experience."

Yet he’s insisted on doing as much as he can, making public appearances and performing state duties despite his health setbacks.

"William and Kate are worried perhaps he’s taking on too much and could be jeopardizing his health," our source said.

His wife, Queen Camilla, 77, meanwhile, is torn between duty and love.

Our insider added: "She's distracted by his illness and overwhelmed by the thought of losing him."

While Charles is focused on his health, William has been consumed by anger aimed at brother Prince Harry, 40, and his 43-year-old wife, said the source – and with carrying out the vengeance his father refuses to do.

In April, it emerged Markle is still using their coveted His/Her Royal Highness titles despite promising the late queen that they would drop them when they left as senior royals in 2020 and moved to California.

"It's been talked about at the palace that when William becomes king, he plans to strip the Sussexes of their HRH titles," our source said.

Days later, William was incredulous again when, after Harry lost his years-long legal appeal against a 2020 government decision stripping him and his family of automatic police protection when they visit Britain, the army veteran blamed the royal family for the move.

In a bombshell May 2 BBC interview, he claimed his father wouldn't speak with him and insisted that despite his long estrangement from Charles and William.

"I would love reconciliation with my family," he said – adding: "There’s no point in continuing to fight anymore. Life is precious. I don’t know how much longer my father has."

The Princess of Wales is also doing her best to protect the monarchy – and her marriage – by supporting her husband.

He and Charles both have notoriously "short fuses," said our source, adding "specially when things don't go their way."

As a senior palace staffer told royal expert Robert Jobson in 2023, the Prince of Wales "can be difficult."

The staffer called him "a driven person," which "can make him impatient" and "short-tempered." In 2024, Jobson shared more, writing in his book The Making of a Modern Monarch that William "can be a bit of a shouter when he loses it."

But Middleton, an advocate for mental health, "knows how to manage these situations, by staying calm and showing empathy, supporting his feelings, and providing a quiet space," said our source.

His ongoing rift with Harry "breaks her heart," added our source, and upsets her to the point that she’s been encouraging William to see both sides and make peace.

If anyone can broker a truce, it’s Kate, "a brilliant arbiter and peacemaker," her uncle Gary Goldsmith said three years ago.

Middleton knows how important image is for the institution, explained the source, "and is wise enough to know this is not the legacy King Charles deserves to leave when he passes."

The insider added: They need to put their differences aside for the monarchy's sake."

Middleton is also fiercely protective of her own children.

As Harry detailed in his memoir, Spare, it's not easy being the sibling of the heir to the throne.

"Harry was clearly damaged by the 'spare' mentality Charles raised him with following Diana's 1997 death," said our source.

Middleton is determined to ensure the next generation of "spares" – younger children Princess Charlotte, 10, and Prince Louis, 7 – get along with the heir, eldest son Prince George, 11.

As she guides them into public life, which most recently included taking them out of school to celebrate the 80th anniversary of VE Day with the royal family, which happened on May 5.

"Kate's supporting their emotional well-being, giving them lots of love and encouragement and letting them express their feelings," explained our source.

As she prepares to be the first commoner to become queen consort since 1471, Middleton isn't afraid to step up.

Back in January, when she announced her cancer was officially in remission, she visited the hospital where she'd quietly undergone chemotherapy months earlier.

There, she told a patient while she was being treated, "everyone said to me, 'Please keep a positive mindset, it makes such a difference.'"

It's advice Middleton can return to now.

While William may have the blue blood entitling him to rule, a royal insider told RadarOnline.com earlier this year: "Kate is the glue that's keeping the monarchy together."