In a statement shared by Buckingham Palace, it was revealed: "His Majesty has been treated for benign prostate enlargement. It was during this intervention that a separate issue of concern was noted and subsequently diagnosed as a form of cancer."
The news has left royal watchers around the world wondering what will happen if King Charles chooses to abdicate the throne. More importantly, what will it mean for his grandchildren; Prince George, Princess Charlotte, and Prince Louis and Prince Archie and Princess Lilibet.
If King Charles were to abdicate, Prince William would become King, while his wife, the Princess of Wales, would take on the role of Queen Consort. That would make Prince George, ten, the heir to the British throne.
Preparing to be a monarch is said to be a lifelong commitment, and one that King Charles and his son Prince William have been dedicated to since their school years. Yet with William at 41, and George just ten years old, a potential abdication will be a major step up for the eldest Wales child.
Nonetheless, it's clear to see that Prince George has already developed the tendencies of a natural leader.
Acting with immaculate manners whenever he's in public, taking part in engagements with his parents, and matching his dad's pristine style in suits and ties, "Prince William, an assertive intuitive father" is helping his son to act with "calm and confidence," global parenting expert Jo Frost, AKA Supernanny, told HELLO!.
"I’m told [Prince George's] informal chats with his grandfather are becoming more frequent," adds royal expert Robert Jobson in The Daily Express. "You sense, just like William’s relationship with the late Queen, Elizabeth II, when he was an Eton schoolboy, George’s close bond with the King will be important in preparing for his future role."
"You learn on the job. There is no rule book," William told British GQ in 2017 on being the future King, adding: "Having that difference in how we do things makes the royal family more interesting and more flexible. If we all followed the same line, it would all be quite stifled. Our characters are different and the different opinions are important to have."
What will happen to Prince Archie and Princess Lilibet if King Charles abdicates?
Despite Prince Harry's strained relationship with his father, he is still in line to the British throne. His children, Prince Archie, four, and Princess Lilibet, two, are too - and should their grandfather abdicate it will affect their line of succession.
Currently Prince Archie is sixth in line, while his younger sister is seventh. The Duke and Duchess of Sussex have put down roots in Montecito, California after officially stepping away from royal duties in 2020, yet the abdication of the King could mean the Sussexes decide to return to the UK in order to support Prince William's life-changing new role.
HELLO!'s Online Royal Correspondent, Danielle Stacey, added: "In the event of an abdication, even if the Sussexes decided to take on an official role in future, it was always likely that Archie and Lilibet would carve out their own careers, much like Harry's cousins, Princess Beatrice and Princess Eugenie.
"The Duke and Duchess rarely share images of Archie and Lilibet, allowing them to grow up as private citizens. I feel this will continue until the Sussex children are older and can make their own decisions about whether they want to step into the public eye."
It was clear during the funeral of Queen Elizabeth II how united her grandchildren were in showing their respect for her reign, and love for one another. A major royal event such as an abdication could bring the estranged cousins closer together.
Danielle added: "Prince Harry's reunion with King Charles, albeit brief, does seem to suggest a path to reconciliation. Harry said of his father in his interview with Oprah Winfrey: "I will always love him. There's a lot of hurt that's happened. I will continue to make it one of my priorities to heal that relationship."
"We also know that Harry called the King on his 75th birthday and he made the trip to the UK last May for the coronation, so they seem to be taking small steps to heal their relationship."
Abdications in British royal history are extremely rare, having not occurred since 1936. They are more common in Europe, however, with Queen Margarethe of Denmark recently abdicating to make way for her son King Frederik following months of ill health.