The king shook hands and spoke with those who had gathered at Windsor and told them: “You’re very brave to stand out here in the cold.”
Charles had smiled and waved at crowds as he arrived for the Easter Mattins Service alongside the queen, joining other members of the royal family – including the Princess Royal and her husband Vice Admiral Sir Timothy Laurence, the Duke and Duchess of Edinburgh, the Duke of York and Sarah, Duchess of York – for the annual event.
It has been the king’s most significant public appearance since his cancer diagnosis.
It comes just over a week after the Princess of Wales released an emotional video message disclosing that she had started a course of preventative chemotherapy.
Kate, the Prince of Wales and their children Prince George, Princess Charlotte and Prince Louis, who all attended the service last year, were absent from the Easter Sunday service.
The family are spending the Easter holidays together as they adjust to Kate’s 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 after the shock news about his daughter-in-law.
But the service was a smaller version of the annual gathering, with fewer members of the royal family, as the king has paused public-facing duties while he continues treatment for cancer himself.
He was described by the palace as being “so proud” of the princess for her courage in speaking out, and is said to be in “the closest contact with his beloved daughter-in-law”.
The king’s own treatment for cancer was announced at the start of February, but he has been carrying out low-key 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.
Earlier 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.
Kate Middleton’s mysterious ‘disappearance’ drama – a timeline
Kate Middleton’s mysterious ‘disappearance’ drama – a timeline
Over the course of the month, he also welcomed a series of foreign officials to Buckingham Palace, including high commissioners of Jamaica, Tanzania and Singapore.
On Tuesday, as the palace announced Charles’s attendance at the Easter Sunday service, he was pictured carrying out official duties for the first time since Kate shared her cancer news with the nation, as he met 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.