King Charles smiles during the recording of his Christmas message at the Fitzrovia Chapel in London on 11 December. Photo: AARON CHOWN / AFP
The King has delivered his annual Christmas message from a former hospital chapel.
New Zealand is the first country in the Commonwealth to broadcast King Charles' message.
King Charles singled out and thanked the medical profession for its dedication and service.
In a break from tradition, the King, who is being treated for an undisclosed form of cancer, spoke from a former hospital chapel, rather than from one of the royal residences.
He praised those who care for others and gave his own personal thanks in the six-minute address.
"All of us go through some form of suffering at some stage in our life, be it mental or physical. The degree to which we help one another, and draw support from each other, be we people of faith or of none, is a measure of our civilisation as nations.
"This is what continually impresses me, as my family and I meet with and listen to those who dedicate their life to helping others."
Speaking from Fitzrovia Chapel in central London, which was previously a hospital chapel before it was demolished in 1924, the king paid tribute to caregivers.
"From a personal point of view, I offer special, heartfelt thanks to the selfless doctors and nurses who this year, have supported me and other members of my family through the uncertainties and anxieties of illness, and have helped provide the strength, care and comfort we have needed.
"I am deeply grateful, too, to all those who have offered us their own kind words of sympathies and encouragement."
The King recalled his recent visit to the South Pacific and Australia, and said he was reminded of "how diversity of culture, ethnicity and faith provide strength, not weakness".
"Across the Commonwealth, we are held together by a willingness to listen to each other," the King said.
King Charles also acknowledged the devastating effects of conflict, pointing to ongoing war in the Middle East, Ukraine and parts of Africa.
The King referred to the biblical Nativity and the history of Christianity in his address.
"The message of the angels to the shepherds, that there should be peace on earth, in fact echoes through all faiths and philosophies. It rings true to this day for people of good will across the world.
"And so it is with this in mind that I wish you, and all those that you love, a most joyful and peaceful Christmas."
The annual speech from the monarch is traditionally recorded earlier in December and broadcast on television and radio at 3pm on Christmas Day in Britain.
The annual festive broadcast is normally recorded at Buckingham Palace or Windsor Castle.
The speech location is a break with tradition amid the King's continued cancer treatment.
The first Christmas Royal broadcast was given by King George V in 1932. Every year since, the monarch has addressed the nation on Christmas Day.