His Majesty has taped a first-hand account concerning his experience with cancer, which will be broadcast as part of this year's annual cancer awareness campaign, spearheaded by medical research organisations and Channel 4.
Official sources said the King would discuss his "recovery journey" as a person living with the disease, in a video message on this Friday at 8pm UK time.
The message, recorded at a royal residence a fortnight ago, will emphasise the vital significance of preventative health checks to ensure more people detect the disease at an initial point.
This constitutes a rare update on the medical condition of the King, who has been in a course of therapy since his condition was announced in the start of 2024. However, it is believed unlikely the King will identify his particular diagnosis.
The annual charity initiative each year generates donations for clinical trials and therapies and encourages people to get check-ups to improve the chances of an early diagnosis.
The King's candid approach about his illness, and managing the disease, has been aimed to raise awareness and to persuade more people to get tested - and this will be escalated with this unusual personal contribution.
So far the King's main approach to his cancer has been to continue his schedule, upholding a hectic timetable despite his ongoing course of care, and he appears not to have wanted to be defined by his condition.
Recently has seen the King, 77, embarking on several international tours, notably to Italy and Canada, and receiving the biggest number of foreign dignitaries to the UK for almost 40 years, featuring the German president recently.
The upcoming charity programme on television, presented by presenters including a team of famous hosts, will encourage people not to be afraid of getting cancer checks.
Each presenter have been had experience with cancer - one host revealed last month she had undergone surgery for a tumour, while Clare Balding was treated for thyroid cancer in the past. Presenter Adam Hills has previously discussed his late father, who had a diagnosis and then later blood cancer.
The show will reach out to the estimated nine million people in the UK who charities estimate are not current with public health checks, with an online checker to let people check if they are able for screenings for several common cancers.
In an effort to clarify screenings and demonstrate the importance of prompt detection there will be a direct feed from treatment centres at Addenbrooke's and Royal Papworth hospitals in Cambridge.
"I want to take the fear surrounding cancer screening and prove the public that they are not isolated in this," stated Davina McCall.
Currently in the UK, there are a number of national health screening services - for bowel, breast and cervical cancer - offered to eligible individuals.
A new lung cancer screening programme is also being gradually implemented for people at high risk of being diagnosed with the condition, focusing on people of a certain age, who are smokers or used to.
Individuals may discuss prostate cancer checks, but there is lacking a standardised service in place.
The fundraising campaign, which has raised a significant sum over the past decade, is supporting multiple medical projects encompassing many patients.
His Majesty, in a message for guests at a gathering for cancer charities in the spring, had discussed acknowledging the "daunting and at times scary experience" for those diagnosed and their support networks.
But he noted his first-hand encounter of managing cancer had revealed that "the most difficult times of disease can be brightened by the support of carers," as he thanked those who cared for cancer patients.
Royal representatives has not made public the nature of cancer the King has, or the medical care he has received. The King's cancer was discovered following he had undergone a prostate procedure.
Lena is a tech journalist with over a decade of experience covering consumer electronics and emerging technologies.