King Charles breaks cover after cancer treatment 'side effects'

King Charles has been spotted for the first time since leaving hospital after suffering 'side effects' of cancer treatment.

According to the Daily Express, the monarch was seen leaving Clarence House after he was briefly hospitalised on Thursday.

King Charles waved at well-wishers while leaving Clarence House by car.

The King on Thursday was forced to cancel his appointments for the rest of the day and Friday after suffering "side effects" from his cancer treatment, Buckingham Palace said.

"Following scheduled and ongoing medical treatment for cancer this morning, the king experienced temporary side effects that required a short period of observation in hospital," the statement said.

"His Majesty´s afternoon engagements were therefore postponed," the statement added, saying that the 76-year-old UK head of state had since returned to his home in Clarence House.

"As a precautionary measure, acting on medical advice, tomorrow´s (Friday´s) diary programme will also be rescheduled."

According to the GB News, King Charles required a short period of observation at The London Clinic following his scheduled medical treatment on Thursday morning.