Queen Camilla has described the King as doing “extremely well under the circumstances” following his cancer diagnosis.
The Queen has said the King is “doing extremely well”, as the 75-year-old monarch continues his cancer treatment.
At a musical evening at Salisbury Cathedral, Queen Camilla also said the King is “touched” by the messages from the public.
The Queen had left the King at Sandringham to fulfil her royal engagement and among the first people she met were medical staff from Wiltshire Air Ambulance.
Ben Abbott, a critical care paramedic, said: “I do hope His Majesty is doing well Ma’am, we’re all really sad to hear the news.”
In her first public words since the diagnosis was announced on Monday, she replied: “He is doing extremely well under the circumstances.
“He is very touched by all of the letters and messages the public have been sending from everywhere. That’s very cheering.”
The King’s cancer treatment as an outpatient started earlier this week, and he returned, with the Queen, to his Sandringham home in Norfolk on Tuesday after seeing Prince Harry in London.
The Duke of Sussex returned to his family in California after he is said to have spent about 45 minutes with his father at Clarence House.
King Charles was diagnosed with a “form of cancer” after he had hospital treatment for an enlarged prostate.
Buckingham Palace has not confirmed what type of cancer he has. But it has said he does not have prostate cancer.
Meanwhile, Prince William returned to royal duties for the first time following his wife’s abdominal operation and the King’s diagnosis.
Arriving at a gala for the London Air Ambulance Service in central London on Wednesday night, the Prince of Wales waved to people gathered outside and said: “We really appreciate everyone’s kind messages, thank you.”