King Charles will be present at the Easter Sunday service

In his most prominent engagement since disclosing a cancer diagnosis, King Charles III of Britain will attend an Easter Sunday church service, Buckingham Palace announced on Tuesday.

The Easter Mattins Service in St George’s Chapel at Windsor Castle is an annual tradition of the British royal family that Charles and his wife, Queen Camilla, will be attending.

The declaration follows Catherine, Princess of Wales, the 75-year-old king’s daughter-in-law, revealing last week that she was also undergoing cancer treatment.

With two of the monarchy’s most senior members battling serious illnesses at the same time, the monarchy finds itself in an unparalleled predicament in contemporary times.

Catherine, forty-two, will become a future queen when she marries Prince William, the eldest son and heir of Charles.

The palace declared in early February, just 17 months into his reign, that Charles had cancer and would be postponing all public appearances while he began treatment.

The type of cancer has not been disclosed.

After being hospitalized in January for surgery to treat a benign prostatic problem, it was discovered that he had an unrelated cancer.

He has been working in the background, going to some in-person meetings, and showing up to more official functions.

He was shown on Tuesday at Buckingham Palace in central London, meeting with representatives from the community and religious communities.

Pictures from last week showed him attending two different engagements at the palace with Korean War veterans and diplomats.

In a statement released earlier this month, Charles said he was “deeply touched” by people’s well-wishes for his health and that he would carry on serving “to the best of my ability.”

He revealed in a video message last week that Kate, as she is often called, was receiving chemotherapy, and he thanked her for her bravery.

After her last public appearance on December 25, she had abdominal surgery in January, at which time cancer was discovered.

At the time, her Kensington Palace administration stated that it would take until after Easter for her to be prepared to resume her public duties.