Kate — Britain’s beloved Princess of Wales — may be facing a secret health crisis and losing her luscious locks due to grueling medical treatments just one year after announcing she was in remission, sources say.

Kate recently appeared beside heir to the throne Prince William, her hubby, at London’s Natural History Museum. But concerned insiders say there was nothing natural about her unusually voluminous blond ’do.

“It looks like a wig. She’s known for her long lustrous full vibrant hair, and it is likely thinning due to all the treatment that she’s undergone,” beauty expert Blake Johnson tells Globe.

Early last year, the 43-year-old mom of three revealed that she had an undisclosed form of cancer that was discovered after abdominal surgery — but in September 2024 shared that she was given the all-clear after completing chemotherapy.

“From what I’m seeing and hearing, she’s testing the idea of having to wear extensions and wigs. Her hair is most likely already thin, and she may be trying to hide some patches,” adds Blake, who also observes that Kate may have lost “20 pounds or more” amid her battle.

 <span class="wp-caption-text">Getty Images</span>

Getty Images

As Globe has reported, sources say Kate took a nearly eight-week break from palace duties at the end of summer to gather her strength to prepare to serve as queen because she’s aware that the reign of King Charles, her father-in-law, may be cut short due to his own cancer diagnosis.

But now there are additional fears for the princess’ well-being — and her signature look.

Correspondent Tom Sykes, author of The Royalist Substack, also expressed suspicion about Kate’s dramatically different hair, conferring with multiple staff at two London wig suppliers, who feel that she likely relied on “expensive” extensions to enhance her crowning glory.

 <span class="wp-caption-text">James Whatling</span>

James Whatling

Blake believes health-conscious Kate would never dye her natural hair with chemicals, given that many of the ingredients are considered carcinogenic.

“That could explain why she would put on a Dolly Parton wig,” he reasons. “She’s trying out different styles and different looks to give her hair some space and time to recover.”

However, days after her shocking blond debut, Kate reverted to her dark brunette style, wearing her more demure coiffure pinned back as she took in the Women’s Rugby World Cup match between England and Australia in East Sussex, per People.

Sources suggest the switchback may have been an attempt to brush off critics who noticed her sickly appearance — and cover up the physical signs of her anguish.