A royal commentator has said that Prince William—heir to the British throne—and his wife Princess of Wales Kate Middleton feel “intense anxiety” at becoming the next monarch and Queen consort of the United Kingdom amid King Charles III cancer journey, the Mirror reported Sunday.

The report said the Duke of Cambridge i.e. Prince William, 41, will be the next monarch and he is supposed to receive support in his duties from his wife Kate, 42, in royal engagements in her new role. The prospect of these positions as the next monarch and Queen consort is said to be causing “intense anxiety” for the royal couple.

“News of Charles’s cancer has put William and Catherine in frightening proximity to ascending the throne … The prospect of it, I am told, is causing them intense anxiety,” the Mirror quoted former Vanity Fair editor Tina Brown as saying.

Earlier, the New York Times reported the members of the public —who attended an Easter Sunday church service with King Charles III —as praising His Majesty’s health, saying he “looked good.”

“I think it’s really significant (Charles’ attendance). It indicates that he’s doing good and that he’s definitely on the incline in relation to his health, so that’s really nice to see. I also would like to thank him for attending the service today because I know that must’ve been a lot, but he shows himself to be committed to this nation and to people all around the world,” said one royal well-wisher at St George’s Chapel.

It is important to note that King Charles III attended the service at St George’s Chapel in Windsor Castle with the Queen in what was his most significant public appearance since his cancer diagnosis. He shook hands and spoke with those who had gathered at the castle in a surprise walkabout following the service. Yet, he does continue to undergo treatment for his cancer, and concern remains.

“Some believe, however, that if Charles and Kate were to be permanently side-lined, forced into greatly reduced roles for the longer term by ongoing health challenges, a Prince William regency would look desperately short-handed. Officials are as busy as ever. There is no question of decisions being taken by anyone other than the king,” Tom Sykes, royal correspondent with Daily Beast, said.

In February, while making the announcement of cancer diagnosis, the British monarch did not specify which type of cancer it is. The statement read: “The King’s recent hospital procedure for benign prostate enlargement, a separate issue of concern was noted. Subsequent diagnostic tests have identified a form of cancer.”