JUST IN: Teary-Eyed Prince William heartbroken after learning the sad Announcement about Kate Middleton’s cancer update. “My wife is going to… See more

Prince William was “completely crestfallen” after learning of his wife Kate Middleton’s cancer diagnosis, a prominent royal author has claimed.

In a prerecorded video on March 22, the Princess of Wales revealed her diagnosis to the world, sharing that she’s been undergoing chemotherapy treatment as a result.

The news came shortly after William’s father, King Charles, shared his own cancer diagnosis in February.

Prince William was “completely crestfallen” after learning of his wife Kate Middleton’s cancer diagnosis, a prominent royal author has claimed.Getty Images

“It was devastating for him,” royal author Robert Jobson told Us Weekly.

Jobson, whose book “Catherine, the Princess of Wales: A Biography of the Future Queen” was released this week, said the heir to the throne immediately felt “a lump in [his] throat,” which was followed by “the empty feeling in his stomach” after the mom of three shared the news globally.

“It wobbled him,” Jobson told the outlet. “There’s no doubt about that.”

The Post has reached out to Kensington Palace for comment.

Following her shocking cancer announcement, the princess stayed away from the public eye to prioritize her treatment process.

The Princess of Wales revealed her cancer diagnosis to the world in March — just weeks after King Charles’Just three months later, the royal wrote in a letter that she was “making good progress” but had “good days and bad days” while going through chemotherapy.

The following day, Middleton joined the royal family for King Charles’ birthday celebrations on the Buckingham Palace balcony at the Trooping the Colour ceremony.

And last month, she attended the Wimbledon tennis championships, which is reportedly her last public outing for the foreseeable future. As his wife continues to prioritize her recovery, William has been faced with challenges of his own.

The Prince of Wales, 42, is reportedly navigating through his rumored crisis talks with estranged brother Prince Harry — as his cousins Princess Beatrice and Zara Tindall have been offering up their support.

William has been forced to increase his workload, all while his fractured rift with his younger brother continues to play out in public.

Former royal staffer Grant Harrold has suggested that the feuding brothers are in private talks to hash out their differences.“You’d like to think this time would bring William and Harry closer, but we don’t really know what’s going on behind closed doors,” said Harrold — who worked for the monarch for seven years between 2004 and 2011.

The Prince of Wales, 42, is reportedly navigating through his rumored crisis talks with estranged brother Prince Harry.“They may well be discussing things and communicating, but it’s very difficult. I have no doubt there will be some kind of communication between the brothers, and between Harry and his father.”

“Of course, a lot has happened, and a lot has to be resolved and sorted out. This may well be on track, but it may not have even been addressed yet,” he added.