King Charles III took a trip to the hospital on Thursday because of side effects from his ongoing cancer treatment.

The king, who was admitted after experiencing side effects from his cancer treatment but quickly released, is “greatly disappointed” to miss meetings with ambassadors.

King Charles III was briefly hospitalized Thursday amid ongoing medical treatment for cancer, according to Buckingham Palace. Charles' hospitalization was a result of "temporary side effects" he experienced after undergoing what the palace described as "scheduled and ongoing medical treatment for cancer" on Thursday morning.