The Princess of Wales recently joined the royal family at Trooping the Colour to put on a united front as she battles cancer.

Could the Prince and Princess of Wales be key to saving a monarchy plagued by a health crisis? Some royal experts seem to think so.

King Charles III, who once expressed his desire for a slimmed-down monarchy, has witnessed several key members of the royal family become sidelined.

Both he and Kate Middleton are battling cancer, and his sister, Princess Anne, recognized as his right-hand woman, has been hospitalized for a concussion.

The Princess of Wales put on a brave face for Trooping the Colour June 15. (Max Mumby/Indigo/Getty Images)

Prince Andrew has been keeping a low profile since his scandal involving Jeffrey Epstein resulted in a nuclear interview in 2019, while the Duke and Duchess of Sussex continue to live in California after making their exit in 2020.

“William and Kate, far and away the most beloved members of the royal family, really are the pillars on which the future of the monarchy rests,” Christopher Andersen, author of “The King,” told Fox News Digital.

“If either one of them starts to wobble, the whole thing can come crashing down. At the moment, Kate is at her most vulnerable. The ground beneath Kate is shifting in major ways. Only time can tell if she can stand strong.”

Royal author and Vanity Fair correspondent Katie Nicholl claimed the palace didn’t have a game plan to address the health woes of several senior members, including Kate Middleton. (Chris Jackson/Getty Images)

Royal author Katie Nicholl recently wrote in Vanity Fair that the palace “did not have a game plan,” following the devastating dual cancer diagnosis for the king, 75, and his daughter-in-law, 42.

“This was not a public scandal or a crisis like an abdication,” Nicholl wrote. “Nevertheless, it forced a rethink for Charles in terms of his slimmed-down monarchy and how best to serve the people. The mighty House of Windsor, which not long ago had the world’s longest-reigning monarch at its helm, suddenly seemed very vulnerable.”

Andersen pointed out that both the king and his elder son William were in full support of a slimmed-down monarchy, one in which only a select group of senior royals would be fulfilling duties for the crown. But after Anne “joined the ranks of stricken senior royals,” it made the palace rethink the strategy.

Prince William, Prince of Wales, wearing a recycled tie, takes a tour of the Innovation Showcase at the Breakthrough Energy Summit on June 27, 2024, in London.  (Chris Jackson/WPA Pool/Getty Images)

Andersen believes all eyes are on William even more now as heir to the throne. As for Kate, everyone seems to be waiting with bated breath for her official return to public life.

Prince William, the elder son of King Charles III and the late Princess Diana, is heir to the British throne. (Chris Jackson/Getty Images)

“The simple truth is that the royal family cannot be whittled down to a precious few without the risk of having it grind to a halt altogether,” Andersen explained. “For over 70 years, the Windsors had longevity on their side – almost to a ridiculous extent. Queen Elizabeth II lived to be 96, and her husband Prince Philip was 99, the longest-living royal male in history.

“The Queen Mother was downing her favorite gin and Dubonnets right up until the end at the astounding age of 101. There seemed to be no need for redundancy, with senior royals seeming practically immortal and three generations of future monarchs … waiting in the wings.”

Queen Elizabeth II, England’s longest-reigning monarch, died in 2022. She was 96. Prince William is heir to the British throne. (Geoff Pugh/Getty Images)

“It’s hard to blame palace officials for not having a plan in place to cope with the simultaneous cancer diagnoses of King Charles and Princess Kate, much less the sidelining of such a valuable supporting player as the Princess Royal,” Andersen continued. “The home team is running out of options.”

British broadcaster and photographer Helena Chard told Fox News Digital that once Kate is fully recovered and ready to go back to work, the public will feel more at ease about the monarchy’s future again.

“The enigmatic and elegant Princess of Wales is integral to the future of the monarchy,” she said. “Everyone is wishing her a full recovery. She just needs a few more months of cancer treatment and peace to get fully fit and well. When she is back to regular work, we will have forgotten about health battles and the fragile monarchy narrative.”

Kate Middleton announced to the world she had cancer in a prerecorded message shared in March 2024. (The Prince and Princess of Wales Twitter)

Royal expert Richard Fitzwilliams agreed.

“The Prince and Princess of Wales have been the future of the monarchy since their marriage,” he explained. “After them, their children … Kate has star power, beauty, poise and dedication. She and William have a very special cachet as a couple. She is championing studies in early childhood, and this is an important cause.

“Princess Anne’s accident this week shows what can happen, quite unexpectedly,” Fitzwilliams shared. “It was she who quite recently said a slimmed-down monarchy was impractical. It depends on what is wanted of the royal family.”

Princess Beatrice, left, and Princess Eugenie, the daughters of Prince Andrew, could step in to help the senior royals. (David M. Benett/Dave Benett/Getty Images)

Several experts agreed not all royals possess the same star power as the Prince and Princess of Wales. Still, they’re considered the most desirable candidates to step in and help.

“Prince Edward and his wife Sophie are doing what they can to take up the slack,” said Andersen. “Princess Beatrice and Princess Eugenie could be asked to pitch in, which would be ironic given that Charles once contemplated stripping Andrew’s daughters of their titles as part of his plan to slim down the monarchy. Not surprisingly, Andrew angrily objected at the time.

Prince Edward, Duke of Edinburgh, and Sophie, Duchess of Edinburgh, attend Ladies Day of Royal Ascot 2024 at Ascot Racecourse June 20, 2024, in Ascot, England.  (Max Mumby/Indigo/Getty Images)

“Still, none of these lesser royals have the star power to replace Kate if, for some reason, she is unavailable,” Andersen added. “Only Prince Harry, whose status in the polls ebbs and flows, might have the wattage to light things up again and keep the party going — if, somehow, he can work his way back into the king’s and William’s good graces. But that is a gargantuan if. For the time being, neither King Charles nor Prince William is willing to budge. The war between the brothers continues.”

The Duke and Duchess of Sussex live in California with their two children. (Getty Images)

Chard suggested other members of the royal family could pitch in — even if they don’t have titles.

“Zara and Mike Tindall and Peter Phillips jump in with energy,” she said. “They add interest, fun and vibrancy to all occasions. I am sure their royal standing could be renegotiated if needed.”

Zara Tindall, the daughter of Princess Anne, is married to former rugby player Mike Tindall. (Samir Hussein/WireImage/Getty Images)

But there is hope for the royals, and the pressure could be eased on the Prince and Princess of Wales.

On June 15, the royal family put on a symbolic display of unity during Trooping the Colour by standing alongside each other on the Buckingham Palace balcony. The event was Kate’s first appearance since she disclosed in March that she was undergoing chemotherapy.

Andersen doesn’t believe the monarchy’s future is bleak. However, the senior royals will have their work cut out for them.

King Charles III waves as he formally bids farewell to Japan’s Emperor Naruhito and Empress Masako at Buckingham Palace in London June 27, 2024. (Chris Jackson/Pool/AFP via Getty Images)

“Is the monarchy more fragile than it’s ever been? People seem to have forgotten the days following Princess Diana’s death, when the British people were so angry over Queen Elizabeth’s seemingly callous indifference that the monarch had to apologize to her subjects and bow to Diana’s passing coffin. That said, this is certainly a trying time for the monarchy, and there are undoubtedly challenging days ahead.

“There must be days when King Charles wishes he’d never heard of the term ‘slimmed-down monarchy.’ The monarchy is being slimmed down for him, and in ways he never could have imagined.”