King Charles gave a rare update on his cancer journey during an engagement last week. The monarch spoke about his health during a visit to Bradford, England, while in conversation with florist Safeena Khan.

Britain's King Charles III has written a private letter to former President Joe Biden, Buckingham Palace said, following the latter's diagnosis of an aggressive form of prostate cancer, which has metastasized to his bones.

The King is currently undergoing treatment for an undisclosed type of cancer PEOPLE can confirm that King Charles wrote a personal note to Joe Biden following the former president’s cancer diagnosis.