King Charles has smiled and waved at members of the public as he arrived for the Easter Sunday service at Windsor Castle, in his most significant public appearance since he was diagnosed with cancer.

Charles, 75, joined Queen Camilla and other members of the royal family for the annual Easter Mattins Service at St George’s Chapel on Sunday.

As they arrived, a member of the public shouted “happy Easter”, to which the King gestured with his arm and responded: “and to you”.

Also present at the service were Anne, the Princess Royal and her husband Vice Admiral Sir Timothy Laurence, Edward and Sophie, the Duke and Duchess of Edinburgh and Andrew, the Duke of York and Sarah, Duchess of York.

Tweet from @KateMansey

The Prince and Princess of Wales, William and Kate, and their children were not present.

The service came just over a week after Princess Kate released an emotional video message disclosing that she had started a course of preventative chemotherapy.

The family are spending the Easter holidays together as they adjust to her cancer diagnosis, which was discovered in post-operative tests after major abdominal surgery.

The King’s attendance at church will be seen as a move to reassure the public amid concerns for his own health and after the shock news about his daughter-in-law.

But the service is a smaller version of the annual gathering, with fewer members of the royal family, after the King paused most public-facing duties while continuing to carry out some official duties behind palace walls.

Towards the end of February, Charles had an audience with Prime Minister Rishi Sunak and held a Privy Council in his first face-to-face official duties since the diagnosis.

In March, the King held an in-person pre-budget audience with Chancellor Jeremy Hunt, had a video call with Canadian Prime Minister Justin Trudeau and had an audience with Baroness Scotland.

Over the course of the month, he welcomed a series of foreign officials to Buckingham Palace, including high commissioners of Jamaica, Tanzania and Singapore.

On Tuesday, as the Palace announced Charles’ attendance at the Easter Sunday service, he was pictured meeting community and faith leaders from across the UK in London.

Ahead of Easter, the King reaffirmed his coronation pledge “not to be served, but to serve” with “my whole heart” in an audio address broadcast to a congregation at Worcester Cathedral where the Royal Maundy Service was held in his absence on Thursday.

-PA