What we know and don't know about the King's cancer diagnosis
King Charles revealed his cancer diagnosis in February - here is everything we know so far.
Watch: King attends Easter Sunday service but Prince and Princess of Wales absent
King Charles is set to return to public duties next week, after taking a break from his public-facing role during his treatment for cancer.
In a statement, Buckingham Palace said: "His Majesty The King will shortly return to public-facing duties after a period of treatment and recuperation following his recent cancer diagnosis.
"To help mark this milestone, The King and Queen will make a joint visit to a cancer treatment centre next Tuesday, where they will meet medical specialists and patients.
"This visit will be the first in a number of external engagements His Majesty will undertake in the weeks ahead."
The palace announced the King's diagnosis, and subsequent break from royal duties, at the beginning of February - although there has been no word as to which kind of cancer Charles has been diagnosed with.
Charles has been receiving care as an outpatient since early February and the announcement will be a boost for the monarchy as it comes to terms with King and the Princess of Wales as cancer patients.
What we know
On 6 February, Buckingham Palace announced that the King had been diagnosed with a form of cancer that had been discovered during treatment Charles had for an enlarged prostate at the London Clinic.
The palace said Charles had begun "regular treatments" and would postpone his public duties, adding that the King "remains wholly positive about his treatment and looks forward to returning to full public duty as soon as possible".
Charles informed his two sons, the Prince of Wales and the Duke of Sussex, personally, and Harry flew in from his home in the US to visit his father in the days that followed.
Watch: Queen says Charles is doing very well as she completes Northern Ireland visit
Although Charles put his public events on hold, he has continued his constitutional role as head of state, which includes paperwork and private meetings.
The palace said Charles had chosen to go public about his cancer treatment because he was a patron of a number of cancer-related charities during his time as the Prince of Wales.
Less than two months after his announcement, Kate revealed that she too had been diagnosed with cancer, following weeks of speculation and conspiracy theories after she underwent abdominal surgery at the same hospital where Charles was treated.
In an emotional video message, the 42-year-old princess said she was undergoing a course of preventative chemotherapy.
Buckingham Palace has previously said that the King hailed Kate for speaking out about her cancer diagnosis, saying: “His Majesty is ‘so proud of Catherine for her courage in speaking as she did’. Following their time in hospital together, His Majesty has ‘remained in the closest contact with his beloved daughter-in-law’.
“Both Their Majesties ‘will continue to offer their love and support to the whole family through this difficult time’.”
On 24 March, the King's nephew, Peter Phillips, the son of the Princess Royal, said his uncle was "frustrated" that his recovery is taking longer than “he would want it to”. In a televised interview, Phillips told Sky News Australia: “I think ultimately he’s hugely frustrated. He’s frustrated that he can’t get on and do everything that he wants to be able to do.
On 31 March, Charles made his most high-profile public appearance since his diagnosis at an Easter Sunday church service.
Charles, 75, waved to well-wishers after he and Queen Camilla arrived by car at the annual Easter Mattins Service at St George’s Chapel at Windsor Castle.
The King and Queen were seated separately from the rest of the congregation inside the church to ensure Charles’s health.
It followed the broadcast of a pre-recorded Easter broadcast on 28 March at a Royal Maundy service in Worcester Cathedral, in which the King stressed the importance of acts of friendship “especially in a time of need” - his first public words since the Princess of Wales revealed she was undergoing chemotherapy.
What we don't know
As with Kate, the type of cancer the King is suffering from has not been revealed, although Buckingham Palace said Charles does not have prostate cancer.
When the King was initially admitted for treatment on an enlarged prostate – prior to the news he had cancer – it was understood he wanted to share news of his health update to encourage others to get themselves checked out. However, the palace has not revealed at what stage the cancer is, how ill the king is nor what type of treatment he is receiving.
It is also clear the diagnosis has impacted the king's ability to carry out some of his public duties, although he will make a return to those duties from next week, it is not clear whether he will have as busy a schedule as he did prior to his diagnosis.