King Charles III was briefly hospitalised for observation and check up on Thursday after experiencing "temporary side effects" related to a cancer treatment.

After being discharged later Thursday, the King, 76, returned to Clarence House and continued his duties, but cancelled Friday engagements due to medical advice, according to the BBC.

Buckingham Palace confirmed the King's cancer diagnosis last year, although he has tried to keep his sickness from interfering with his official duties.

In recent weeks, he has visited Northern Ireland, welcomed US President Donald Trump for a diplomatic summit in London, met with Ukrainian President Volodymyr Zelensky to show support for Kyiv's battle against Russia, and attended a Commonwealth Day service, BBC reported.

Despite his brief stay on Thursday, Buckingham Palace said the King will resume his full schedule of duties next week.