King Charles, smiling in first appearance after cancer diagnosis. The monarch attended the Easter service VIDEO

King Charles attended the annual Easter Sunday service at St. George of Windsor Castle, this being his first major public appearance since being diagnosed with cancer, The Guardian reports.

The sovereign, 75, smiled and waved alongside Queen Camilla at the Easter service at St George’s Chapel.

Also in attendance were the Duke and Duchess of Edinburgh and their son James, Princess Anne and her husband Timothy Laurence, and the Duke and Duchess of York.

Kate Middleton, Prince William and their three children did not attend the service as the Princess of Wales continues her cancer treatment.

During the Easter service, the Archbishop of Canterbury, Justin Welby, wished the King and Princess of Wales well and urged the faithful to pray for them during their treatments.

Welby also praised the royals for their dignity and praised them for their “unselfishness”, which he said “encourages others” to do the same.

Kate Middleton revealed on Friday, March 22 that she has been diagnosed with cancer and is in “early stages” of the treatment. The announcement came two months after she temporarily stepped away from public life following what Kensington Palace said at the time was surgery for a non-cancerous abdominal condition.

The sovereign’s cancer was diagnosed in January, and the diagnosis was made public in early February.

King Charles has continued to work during his treatment, but engagements have so far been held in private. Earlier this week, he stated that he was “very sad” that he missed Maundy Thursday service. However, Queen Camilla attended the service.