Who would succeed King Charles III? Everything to know about British royal line.

As questions swirl around King Charles III's health, thoughts immediately turn to the British royal line of succession and who will inherit the throne, less than two years after Charles ascended.

Prince William, who is first in line to the throne, was already taking on more responsibilities after his father Charles sought treatment for an enlarged prostate last month and when wife Princess Kate postponed her appearances at royal events until Easter as she recovers from an abdominal surgery.

Now amid Charles' cancer diagnosis, William, The Prince of Wales, would step up as the heir to the British royal family should anything happen to his father.

"During The King's recent hospital procedure for benign prostate enlargement, a separate issue of concern was noted. Subsequent diagnostic tests have identified a form of cancer," Buckingham Palace said in a statement on Monday.

The palace also informed that Charles was "advised by doctors to postpone public-facing duties" amid his treatment.

Still, there are plenty of questions surrounding the king's reign, what happens after his death and what his death would mean for the British monarchy.

Here is everything we know.

Prince William likely to step up amid King Charles III's cancer diagnosis, experts say

Who succeeds the king?

After 70 years on the throne, Queen Elizabeth II died in September 2022 at Balmoral Castle in Scotland. Charles instantly became king and his wife, Camilla, formerly the Duchess of Cornwall, became the Queen Consort, a request made by the former monarch. (Charles was previously married to the late Princess Diana.)

After Charles, the line of succession turns to his older son William. William's children — Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5 — are next in the line of succession, followed by Prince Harry and his children, Archie, 4, and Lilibet, 2.

The succession is as follows:

1. Prince William, Prince of Wales

2. Prince George of Wales

3. Princess Charlotte of Wales

4. Prince Louis of Wales

5. Prince Harry, Duke of Sussex

6. Prince Archie of Sussex

7. Princess Lilibet of Sussex

8. Prince Andrew, The Duke of York

9. Princess Beatrice, Mrs. Edoardo Mapelli Mozzi

10. Miss Sienna Mapelli Mozzi

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How old is King Charles?

Charles is 75. At 73, he was the oldest recorded person to become a British monarch: King William IV was 64 when he was crowned in 1830.

King Charles III diagnosed with cancer following hospitalization for prostate procedure

What is Operation London Bridge?

Details of Operation London Bridge, as the monarch's funeral plan is known, describes what happens during the 10-day period from the day after the death and the funeral at Westminster Abbey followed by interment in St George's Chapel at Windsor Castle.

The state funeral is held at Westminster Abbey, where the king will lie in state. There will be a committal service in St George’s Chapel, followed by burial in the royal vault's King George VI Memorial Chapel.

What happens immediately after King Charles dies?

• At the moment of the sovereign's death, his eldest son and heir, Prince William the Prince of Wales, instantly becomes Britain's 43rd monarch since William the Conqueror in 1066.

• The new king will receive Parliament's motion of condolence at Westminster Hall, then depart on a tour of the kingdom to meet his people.

• The procession of the coffin from Buckingham Palace to the Palace of Westminster will take place, followed by a service in Westminster Hall.

• The king lies in state at Westminster Hall.

• The king's state funeral will be at Westminster Abbey. The day will be declared a Day of National Mourning and two minutes of silence will be marked across the nation.

Contributing: Hannah Yasharoff, Amy Haneline and Maria Puente, USA TODAY; and The Associated Press

This article originally appeared on USA TODAY: Who becomes king after Charles? Here's the heir to the throne