The Monarch has taped a personal message about his journey with cancer, which will be broadcast as part of this year's annual cancer awareness campaign, run by medical research organisations and Channel 4.
Buckingham Palace stated the King would reflect on his "recovery journey" as a individual battling cancer, in a video message on this Friday at 8pm UK time.
The address, taped inside a royal residence recently, will emphasise the critical nature of cancer screening checks to increase the likelihood more people detect the illness at an initial point.
This constitutes a infrequent public commentary on the medical condition of the King, who has been in a course of therapy since his condition was announced in early last year. However, it is believed doubtful the King will disclose his type of cancer.
The awareness event each year collects money for clinical trials and patient care and prompts people to get health assessments to boost the chances of an early diagnosis.
The King's candid approach about his illness, and managing the disease, has been designed to increase understanding and to persuade more people to get tested - and this will be escalated with this unique personal contribution.
Up until now the King's key philosophy to his cancer has been to maintain his duties, upholding a full diary despite his ongoing course of therapy, and he is understood not to have sought to be defined by his diagnosis.
This year has seen the King, 77, taking several overseas trips, notably to Italy and Canada, and hosting the biggest number of foreign dignitaries to the UK for almost 40 years, which included the German president in recent days.
Friday evening's Stand Up to Cancer show on Channel 4, hosted by presenters such as Davina McCall, Adam Hills and Clare Balding, will urge people not to be afraid of getting cancer checks.
Each presenter have been had experience with cancer - Davina McCall disclosed in November she had received treatment for breast cancer, while another presenter was overcame the illness over a decade ago. Presenter Adam Hills has previously discussed his father, who had a diagnosis and then later leukaemia.
The broadcast will target the estimated millions of people in the UK who charities says are not up to date with public health checks, with an online checker to let people check if they are qualified for tests for breast, bowel and cervical cancer.
In an bid to explain screenings and illustrate the value of prompt detection there will be a live broadcast from hospital departments at medical facilities in Cambridge.
"The goal is to take the fear surrounding health checks and prove everyone that they are not alone in this," said a presenter.
At present in the UK, there are a number of NHS cancer screening programmes - for major health concerns - offered to eligible individuals.
A emerging scheme for lung health is also being slowly rolled out for people at high risk of developing the illness, focusing on people aged 55-74 years old, who are smokers or were former smokers.
Individuals may enquire about prostate cancer checks, but there is no national programme operational.
The Stand Up to Cancer project, which has collected over one hundred million pounds for many years, is financing 73 medical projects encompassing thousands of patients.
King Charles, in a message for guests at a gathering for cancer charities in earlier this year, had spoken of acknowledging the "intimidating and at times scary reality" for cancer sufferers and their loved ones.
But he stated his personal journey of coping with cancer had revealed that "the darkest moments of illness can be illuminated by the support of carers," as he commended those who supported those receiving treatment.
The Palace has not made public the nature of cancer the King has, or the medical care he has been given. The King's cancer was identified after he had had a routine operation.
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