A smiling King Charles III attended the Easter Sunday service at St. George’s Chapel in Windsor, marking the British monarch’s first major public appearance since his cancer diagnosis was made public last month.

The 75-year-old royal was joined by wife Queen Camilla, 76, as the couple walked up waving to the gathered crowds outside the chapel, where royals have traditionally attended the annual holy service.

Prince William and his wife Kate Middleton did not join the tradition this year after the Princess of Wales revealed her own cancer diagnosis last week and said she was undergoing “preventative chemotherapy”.

The King’s public appearance, which is not believed to indicate a full-time return to all his public-facing duties yet as he continues to undergo outpatient treatment, is seen as a move to reassure the British public after his daughter-in-law’s video message sharing the news of her cancer – with Buckingham Palace not revealing the form of cancer in either of the royal’s diagnoses for their privacy.

"We pray for her and the King in their dignified response and we pray for all those who are suffering the same way," the Archbishop of Canterbury, Reverend Justin Welby, said in his Easter sermon at Canterbury Cathedral earlier on Sunday.

British Prime Minister Rishi Sunak spoke of the charities and volunteer organisations that support those in need in his official Easter message and described the festival as a chance to pause and reflect.

“This weekend, as people come together to celebrate and reflect on the message at the heart of the Easter festival, I want to pay tribute to the incredible work of Christians in this country. To the churches, charities, volunteers and fundraisers who live the Christian values of compassion, charity and self-sacrifice, supporting those in need and demonstrating what it means to ‘love thy neighbour’,” said Sunak in his message released by Downing Street.

“Many, I know, will also be thinking of those in pain and suffering around the world and Christians, persecuted because of their faith, who are unable to celebrate Easter freely. For many of us in the UK, Easter is a chance to pause and reflect and an opportunity to spend some precious time with our families and a moment to enjoy the start of spring. So this weekend, let me wish you all a very happy and peaceful Easter,” he said.

Labour leader Sir Keir Starmer spoke of a time for "new beginnings" in his Easter message, with reference to the coming general election later this year.

“The Easter story is one of hope and renewal, of overcoming adversity and light prevailing over darkness. As families and friends gather to celebrate the holiday we turn our thoughts towards new beginnings, our future and how things can change for the better," said Starmer, during a visit to St. Martin-in-the-Fields church in London.

"This Easter I'd like to express my gratitude to the Christian community in the UK and beyond, for their generosity and compassion. At this time of optimism and new beginnings, I thank them for everything they do," he said.

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