His Majesty has recorded a intimate address about his experience with cancer, which will be broadcast as part of this year's Stand Up To Cancer initiative, spearheaded by a leading cancer charity and a television broadcaster.
The royal household said the King would reflect on his "path to recovery" as a person living with the disease, in a televised statement on Friday evening at the evening slot.
The message, taped inside Clarence House a fortnight ago, will highlight the critical nature of routine screenings to increase the likelihood more people diagnose the disease at an initial point.
This will be a uncommon insight on the medical condition of the Monarch, who has been receiving ongoing care since revealing his diagnosis in early last year. Analysts suggest improbable the King will disclose his type of cancer.
The annual charity event each year raises funds for scientific studies and treatment and urges people to get check-ups to increase the probability of an prompt identification.
The King's candid approach about his health challenge, and living with cancer, has been intended to raise awareness and to encourage more people to get screened - and this will be escalated with this exceptional direct participation.
Up until now the King's main approach to his cancer has been to continue his schedule, preserving a hectic timetable alongside his frequent sessions of treatment, and he is understood not to have sought to be defined by his condition.
This year has seen the 77-year-old Monarch, taking several overseas trips, such as visits to Italy and Canada, and hosting the largest volume of foreign dignitaries to the UK for decades, which included the German president in recent days.
Friday evening's Stand Up to Cancer broadcast on television, hosted by presenters including several TV personalities, will appeal to people not to be frightened of getting cancer checks.
The hosts have been affected by cancer - McCall disclosed in November she had received treatment for breast cancer, while Balding was overcame a thyroid condition more than 15 years ago. Host Adam Hills has previously spoken about his late father, who had a diagnosis and then later blood cancer.
The broadcast will reach out to the approximate millions of people in the UK who Cancer Research UK estimate are not up to date 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 attempt to explain screenings and demonstrate the importance of early diagnosis there will be a real-time transmission from cancer clinics at medical facilities in Cambridge.
"The goal is to reduce the stigma surrounding health checks and demonstrate everyone that they are not alone in this," commented a presenter.
Currently in the UK, there are a number of NHS cancer screening programmes - for major health concerns - offered to specific demographics.
A recently launched lung cancer screening programme is also being slowly rolled out for people at potential risk of contracting the illness, focusing on people aged 55-74 years old, who are smokers or have smoked in the past.
Men may enquire about specific tests, but there is lacking a standardised service currently available.
The fundraising initiative, which has collected a significant sum over the past decade, is funding dozens of clinical trials involving many patients.
King Charles, in a statement for attendees at a gathering for related organisations in earlier this year, had referred to understanding the "daunting and at times scary reality" for cancer sufferers and their support networks.
But he stated his experience of managing cancer had demonstrated that "the most difficult times of disease can be alleviated by the kindness of others," as he thanked those who cared for cancer patients.
Royal representatives has not revealed the nature of cancer the King has, or the medical care he has received. The King's cancer was identified after he had had a routine operation.
A tech enthusiast and business strategist with over a decade of experience in digital transformation and startup consulting.