After spending more than seven decades waiting to become sovereign, Britain's King Charles has been diagnosed with a form of cancer less than 18 months since he ascended to the throne.

Buckingham Palace announced Monday that Charles, 75, would postpone public-facing duties while he undergoes treatment but was looking forward to returning to full public duty as soon as possible.

Charles became monarch on the death of his mother Queen Elizabeth on Sept. 8, 2022, having been the longest-serving heir apparent in British history. He was crowned on May 6, 2023.