The king is scheduled to meet face-to-face in London next week despite continuing cancer treatment.
Charles, 75, will likely travel to coincide with his medical appointment and work in the capital area for a day or so.
He has been based in Sandringham since being discharged from hospital last week following prostate surgery.
He flew to London on Monday to undergo treatment for an undisclosed amount of cancer, before returning to Norfolk.
But officials say the king is healthy enough to hold a limited number of face-to-face meetings.
Duchess Camilla said King Charles, 75, who received his first treatment earlier this week, is “very touched” by all the messages of support he is receiving from around the world.
Queen Camilla said: “He is doing extremely well under the circumstances.” He is very touched by all the letters and messages that the public has sent from all over. That makes me very happy. ”
The 76-year-old made the remarks as she arrived at Salisbury Cathedral for a benefit music evening.
The Queen had long planned to attend an evening of music celebrating the work of three Wiltshire charities and traveled five hours from her husband’s side of Sandringham to get to the venue.
She is a strong supporter of Wiltshire Bobby Van Trust, Wiltshire Air Ambulance, Community First and the regimental charities of the Grenadier Guards and The Rifles.
However, her visit almost never materialized due to poor weather and the king being recuperated for initial treatment for an undisclosed form of cancer.
Camilla has not left her husband’s side since his diagnosis and has been with him in Norfolk all this week as he recovers.
Kensington Palace also announced that Prince William’s fourth Earthshot Prize ceremony will be held in Cape Town in November.