His Majesty has filmed a first-hand account concerning his experience with cancer, scheduled for transmission as part of this year's annual cancer awareness initiative, spearheaded by Cancer Research UK and a major network.
Buckingham Palace confirmed the King would reflect on his "recovery journey" as a cancer patient, in a televised statement on Friday evening at 20:00 GMT.
The message, filmed within a royal residence a fortnight ago, will emphasise the vital significance of cancer screening checks to increase the likelihood more people diagnose the disease at an treatable phase.
This represents a infrequent public commentary on the health of the Sovereign, who has been receiving ongoing care since his condition was announced in February 2024. But it is thought improbable the King will disclose his specific form of cancer.
The Stand Up To Cancer event each year collects money for scientific studies and treatment and prompts people to get check-ups to boost the chances of an prompt identification.
The King's relative openness about his condition, and his experience as a patient, has been aimed to raise awareness and to persuade more people to get checked - and this will be taken a step further with this exceptional royal involvement.
To date the King's main approach to his cancer has been to maintain his duties, upholding a hectic timetable despite his ongoing course of therapy, and he appears not to have desired to be defined by his diagnosis.
This year has seen the Sovereign, taking several overseas trips, including to Italy and Canada, and hosting the largest volume of foreign dignitaries to the UK for almost 40 years, including the German president last week.
This Friday's charity broadcast on Channel 4, presented by presenters like a team of famous hosts, will appeal to people not to be afraid of getting preventative tests.
All three have been personally touched by cancer - one host said in November she had received treatment for the disease, while Clare Balding was diagnosed with the illness more than 15 years ago. Comedian Hills has previously mentioned his late father, who had a diagnosis and then later another illness.
The programme will target the estimated nine million people in the UK who Cancer Research UK estimate are not compliant with public health checks, with an website to let people determine if they are able for tests for breast, bowel and cervical cancer.
In an effort to demystify cancer checks and show the importance of early diagnosis there will be a direct feed from cancer clinics at Addenbrooke's and Royal Papworth hospitals in Cambridge.
"The goal is to take the fear from cancer screening and prove everyone that they are not isolated in this," stated one of the hosts.
At present in the UK, there are three national health screening services - for major health concerns - offered to specific demographics.
A emerging scheme for lung health is also being gradually implemented for people at increased risk of developing the disease, specifically targeting people aged 55-74 years old, who are smokers or used to.
Men may enquire about specific tests, but there is not a universal scheme operational.
The Stand Up to Cancer campaign, which has raised over one hundred million pounds over the past decade, is funding multiple clinical trials involving 13,000 patients.
The Monarch, in a message for attendees at a reception for cancer charities in April, had discussed understanding the "overwhelming and at times frightening reality" for cancer sufferers and their support networks.
But he said his experience of coping with cancer had shown him that "periods of great challenge of disease can be alleviated by the greatest compassion," as he praised those who looked after cancer patients.
The Palace has not revealed the nature of cancer the King has, or what treatment he has undergone. The King's cancer was identified following he had received a routine operation.
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