Britain’s King Charles attended the annual Easter church service in Windsor on Sunday, his first appearance at a public royal event since his cancer diagnosis was announced in February.

Charles, 75, waved as he and Queen Camilla arrived by car at St George’s Chapel, the resting place of his late mother Queen Elizabeth, for the service.

Charles has postponed all previous public engagements since Buckingham Palace announced he was to undergo treatment for an unspecified form of cancer which was found in tests after he had a corrective procedure to an enlarged prostate in January.

While the king attended church on Sunday, his son Prince William and his family notably did not. William’s wife Kate said earlier this month she was undergoing preventative chemotherapy after cancer was discovered following abdominal surgery in January.

Charles has kept up with the bulk of his non-public state duties such as greeting foreign officials and holding regular meetings with Prime Minister Rishi Sunak.

Last week, he did not attend an annual Maundy Thursday service but issued an audio message which aired at the event, in which he expressed his sorrow at not being there and wished the public a happy Easter.