The king will hold face-to-face meetings in London next week despite his ongoing cancer treatment.
Charles, 75, will work in the capital for about a day on a trip that is likely to coincide with medical appointments.
He has been staying at Sandringham since leaving hospital last week after prostate surgery.
He flew to London on Monday to undergo treatment for his unknown cancer, before returning to Norfolk.
But sources say the king is well enough to hold a limited number of face-to-face meetings.
King Charles III and Queen Camilla attend Sunday service at the Church of St. Mary Magdalene on the Sandringham Estate on February 4
Camilla said King Charles, 75, who underwent his first treatment earlier this week, was ‘very touched’ by all the messages of support he has received
The King’s helicopter lands at Buckingham Palace, London, following the announcement of King Charles III’s cancer diagnosis
Camilla said 75-year-old King Charles, who underwent his first treatment earlier this week, was “very touched” by all the messages of support he has received from around the world.
Queen Camilla said: “He is doing extremely well considering the circumstances. He is very touched by all the letters and messages that the public has sent from everywhere. That’s very cheerful.’
The 76-year-old made the comments as she arrived at Salisbury Cathedral for a charity musical evening.
The Queen has long been due to attend the musical evening to celebrate the work of three Wiltshire charities and traveled five hours from her husband’s side to Sandringham to attend.
She is a strong supporter of The Wiltshire Bobby Van Trust, The Wiltshire Air Ambulance and Community First, as well as the regiment’s charities, the Grenadier Guards and The Rifles.
But thanks to bad weather and the king’s recovery for his first treatment for his unknown cancer, her visit almost didn’t happen.
Camilla, who has not left her husband’s side since his diagnosis, has been with him in Norfolk all week as he recovers.
Kensington Palace has also announced that Prince William’s fourth annual Earthshot Prize ceremony will take place in Cape Town in November.