The King’s public appearance on Easter Sunday will be a “form of reassurance” to people in the wake of the royal family’s recent health announcements, an expert on the monarchy has said.

Charles, who is undergoing treatment for cancer, smiled and waved at crowds as he arrived for the annual Easter Mattins Service at St George’s Chapel at Windsor Castle on Sunday morning.

The managing editor of Majesty magazine, Joe Little, said the “hugely encouraging” event would help draw the focus away from the Princess of Wales, who disclosed just over a week ago that she had started a course of preventative chemotherapy.

Kate, the Prince of Wales and their children Prince George, Princess Charlotte and Prince Louis, were absent from the Easter service as the family are spending the holiday together as they adjust to her diagnosis.

Mr Little told the PA news agency: “There’s been lots of reports that (the royal family) has been going through a crisis, a period of instability, which I always thought was overdoing it, but I think it will be a form of reassurance to people today that all is well.

“Clearly, there is still some progress to be made but the fact that what happened today actually happened at all is hugely encouraging.”

The King greeted a long line of well-wishers after re-emerging from the church at the conclusion of the service.

Mr Little told PA: “I’m sure it meant a great deal to the King as well.

“It’s the first time that he’s been able to meet the public in such a way for several months, the first opportunity to do a walkabout this year, so it’s a very welcome milestone on the road to recovery.”

The expert added that Sunday’s events were positive for the royal family going forward.

He said: “The King having been diagnosed with cancer always puts a big question mark as to what he can do and when he can do it, so the feeling is now that we will see more of him in the coming months in a public role.”

“The King doing what he did this morning would clearly not have happened if the doctors hadn’t wanted him to do that,” Mr Little continued. “And he obviously felt well enough to do it so that in itself is a very positive sign.”

Asked if the events will help take the focus off Kate, Mr Little told PA: “You would certainly hope so.”

He said he thought the focus had already moved away from her “to a certain extent” this week.

“I think people accept and understand that the Prince and Princess of Wales and their family are on Easter holiday now and that they need their privacy… (to) just get on with being a family,” the royal expert continued.

“I think whatever the King has done today wouldn’t have been with that specifically in mind, but it certainly helps.”