The event at St. George's Chapel will be attended by other royal family members, but Prince William and Kate, the Princess of Wales, who is also undergoing cancer treatment, will not be present.

Charles has suspended most of his public engagements during his treatment.

Charles, the British monarch, has been diagnosed with cancer, but it's not related to his recent treatment for a benign prostate condition.

He is continuing with his duties, including meetings with Prime Minister Rishi Sunak, and will not be handing over his constitutional role as head of state.

On Tuesday, Charles met with community and faith leaders at Buckingham Palace to discuss their work on social cohesion.

The specific type of cancer Charles has not been disclosed.