Current British Prime Minister Rishi Sunak then shared that he was "shocked" and "sad" to hear of the King's declining health.
"Obviously, like everyone else, shocked and sad, and just all our thoughts are with him and his family. Thankfully, this has been caught early," he shared whilst live on BBC Radio 5.
"That's what we're all hoping and praying for, and I'm of course in regular contact with him and will continue to communicate with him as normal," he continued.
First Minister of Northern Ireland, Michelle O’Neill added: “I am very sorry to hear of King Charles's illness and I want to wish him well for his treatment and a full and speedy recovery.”
Singer-songwriter and long-time close friend of King Charles, Gary Barlow, spoke on Sunrise and said, "As a Brit, we love our royal family, we really do. It's very, very sad..."
"I'm hoping that it is good news, but even as a Dad and a husband and a grandad, we are sending our best wishes for sure.
"I've been lucky enough to be around the Royal family enough to know how hard [they work] and how seriously they take their position. All the love and hope to their family.”
Rob Jobson, Sunrise royal editor, the King's royal biographer, and close friend, shared insight on Charles' diagnosis in a conversation with Nat and Shirvo while on air.
“It is a tough time for him - he has confirmed. But he is a pretty stoic character, pretty pragmatic, he has a good medical team and he is pretty fit," he said.
"So, I think he’s got all the signs that he will come through this, and he they have caught it early because he has good medical treatment.
“But it is still cancer and still something they have got to deal with.”