Kate Middleton has become one of King Charles' most beloved family members, with one royal expert calling her the "monarchy's greatest asset."
The claim came from Vanity Fair royal correspondent Katie Nicholl, co-host of "The Royals Uncensored." After more than 20 years covering the royal family on tours and engagements, Nicholl said she has spoken to countless palace insiders, many of whom are enchanted by the Princess of Wales.
"I think Catherine, the Princess of Wales, has always been a very valuable asset to the royal family," Nicholl told Fox News Digital. "She is the commoner who married into the royal family ... [She has made] a seamless transition into that unique world of royalty. It's not easy ... There's a huge amount of sacrifice that goes into being a member of the royal family."
PRINCE WILLIAM, KATE MIDDLETON FINALLY FEEL FREE TO SHOW AFFECTION IN PUBLIC: EXPERTS
"Catherine's had to give up a huge amount, and yet she does it all with a great deal of grace and dignity, always with a smile," Nicholl said. "So she is absolutely the monarchy's greatest asset."
Nicholl also noted that "the king adores her, and the queen adores her."
Royal experts told Fox News Digital that Charles and Kate have forged an even deeper bond since both were diagnosed with cancer. Buckingham Palace announced the king's diagnosis in 2024. In December 2025, Charles shared the "good news" that his treatment would be scaled back in 2026.
WATCH: KATE MIDDLETON IS 'THE MONARCHY'S GREATEST ASSET: EXPERT'
Just weeks after the king's announcement, Kate revealed in March 2024 that she was undergoing treatment for an undisclosed form of cancer. She completed chemotherapy that September and announced in January 2025 that she was in remission.
British broadcaster and photographer Helena Chard told Fox News Digital that the king, 77, had been greatly inspired by the Princess of Wales' strength.
"King Charles sees enormous value in Princess Catherine," Chard said. "Not just as the wife of his heir, but as the cornerstone of the monarchy itself. He genuinely loves his 'darling' daughter-in-law. His face lights up when he is with her. They share similar interests, and they have shared a similar cancer journey, one that has created a deep bond and understanding that goes beyond duty."
Chard argued that it hasn't just been Charles who quickly realized that Kate represented the monarchy's future.
"The late queen saw it too," Chard said. "She recognized Catherine's superpowers early on — her ability to listen, find solutions and bring calm to difficult situations."
"King Charles fundamentally views his time on the throne as stewardship," she said. "He sees himself as the caretaker of the institution and is acutely conscious of preparing the next generation. Collaborative preparation between the king and his heir is essential. Having Princess Catherine as the wife of his heir, Charles has struck gold."
CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTER
Royal author Sally Bedell Smith previously told People magazine that Kate is "like the daughter he never had."
"He has always had a very strong bond with her," Smith told the outlet. "He shares with William an impulse to protect her. They are in this together, Kate and the king."
When Kate made her diagnosis public, Buckingham Palace said Charles was "so proud of Catherine for her courage in speaking as he did."
Author Christopher Andersen previously wrote in his book "Kate!" that the king was by Kate's side "to lend his cherished daughter-in-law moral support" during her health battle.
Kate's advocacy work following her cancer diagnosis continues, Nicholl told Fox News Digital.
"Thankfully, despite a serious health issue, she has overcome that," Nicholl said. "We've just seen her climb the three highest peaks in the United Kingdom to raise money for the Royal Marsden. She's turning her experience into something positive, and I think that's earned her a great deal of respect among the British public, along with a lot of love and affection. People are very much behind her and William."
LIKE WHAT YOU’RE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWS
Chard echoed those sentiments.
"Princess Catherine connects with people in a way that restores faith in the monarchy," Chard said. "She has learned every aspect of the institution over many years and has blended in carefully without fuss. Princess Catherine is central to the institution's success, and King Charles knows this."
With a slimmed down monarchy, Charles needs key allies now more than ever. His younger brother, Andrew Mountbatten-Windsor, stepped back as a working royal in 2019 following his controversial ties to late convicted sex offender Jeffrey Epstein. Charles has since formally removed Andrew’s princely title and HRH style.
In 2020, Prince Harry and Meghan Markle, the Duke and Duchess of Sussex, stepped back as senior working royals and later settled in California.
"Princess Anne and other senior working royals are all stretched thin — and none of them are young," author Catherine Mayer previously told People magazine. "William and Catherine carry the whole thing."
Sources told the outlet there had been "even greater attention and expectation on the Waleses." Still, royal experts told Fox News Digital that Kate is well-positioned to support the king.
"Naturally, King Charles recognizes the value of Kate, who is indeed the monarchy's greatest asset," Richard Fitzwilliams told Fox News Digital. "We should add, 'together with her partnership with William and their family.' While we praise Catherine's many strengths, William is the future king. She will one day be queen consort. They see themselves as a close-knit couple."
"William is currently at the center of reports that he and the king differ over how to handle Prince Harry, in particular," Fitzwilliams said. "As she showed when the Sussexes met with the king and Queen Camilla, she fully supports William's approach."
As William and Kate prepare for their future roles, they are likely to remain under close public scrutiny. With Charles' support, royal experts believe the couple is well-positioned for the years ahead.
"It’s not at all surprising King Charles and Princess Catherine have bonded," British royals expert Hilary Fordwich told Fox News Digital. "One can tangibly feel the public also values her wonderful assets from the reception she always receives when in public, as well as in opinion polls. She has become indispensable and has won the public’s trust."
"Charles can depend on Catherine because she is consistent, steady and modern in her approach to family, shaped by her upbringing and dedication to duty," Fordwich said. "She handled the strain of her cancer battle with dignity, without any indication of self-pity."
"One can observe from the body language between Charles and Catherine that they are so comfortable together, derived from the time they spent together during their cancer battles."