The Queen said the King is "fine" and "looking forward to getting back to work" as he awaits treatment for an enlarged prostate.
Camilla gave an update on Charles, 75, as she made a solo visit to the Aberdeen Art Gallery on Thursday to open its new Safe Space initiative.
The Queen was asked about the monarch's health by the city's civic head, the Lord Provost David Cameron.
"He's fine, thank you very much. Looking forward to getting back to work," Camilla replied.
Charles, who is at his private home Birkhall in Aberdeenshire, is preparing for a corrective procedure next week for the benign prostate condition.
Buckingham Palace, in an unprecedented double royal health scare, announced the King's diagnosis on Wednesday just an hour-and-a-half after Kensington Palace revealed the Princess of Wales had undergone abdominal surgery.
The Prince of Wales visited this wife on Thursday as she spent a third day in hospital recuperating from the procedure.
A serious-looking William was seen leaving the private London Clinic at about 12.35pm.
The heir to the throne drove himself away from the hospital in an Audi e-Tron GT Carbon Vorsprung, followed by a Land Rover Discovery, and left by the back entrance during the low-key, private visit.
Kensington Palace said: "The Prince has just left hospital after visiting his wife."
The princess was admitted on Tuesday for the successful, planned procedure but is expected to stay in the clinic for 10 to 14 days before returning to her Adelaide Cottage home in Windsor.
Kate, 42, is said to be "doing well" but will spend up to three months away from royal duties, with the Prince of Wales clearing his diary and stepping back temporarily from his official role to care for his wife and children.
The couple’s planned trip to Rome in the spring is on hold, with the princess no longer expected to travel abroad in the coming months. A scheduled foreign military engagement could also be affected.
The Times said other events she is likely to miss include the Baftas in February, which she and William often attend, and the long-standing royal tradition of handing out shamrocks to the Irish Guards on St Patrick’s Day in March.
The nature of the princess's condition has not been revealed although Kensington Palace confirmed it was not cancerous.
It is serious enough, however, for future king William to be postponing official duties while his wife is in hospital and in the immediate aftermath.
The princess is not expected to return to public duties until after Easter but this will depend on medical advice at the time.
The King is said to be in touch with the Waleses, with a source describing them as a “close family”.Charities the princess has worked with sent her messages of support, wishing her a speedy recovery.
The Baby Bank, where Kate took George, Charlotte and Louis to volunteer by sorting donations in Holyport near Maidenhead, sympathised with the princess, saying the journey back to full health when you have young children can be difficult.
Rebecca Mistry and Lauren Hall, co-chief executives, said: "We wish the Princess a speedy recovery and know ourselves that with young children that's not always possible."
They added: "We can recommend some books to read whilst she recovers."
East Anglia's Children's Hospices (EACH), of which Kate is patron, said to the princess: "We are all thinking of you."
EACH added on X: "Everyone at East Anglia's Children's Hospices sends their very best wishes to our wonderful patron, HRH The Princess of Wales."
Nigel Clarke, who founded the Dadvengers community group for fathers and their children which Kate visited in November, said: "All of the team at Dadvengers wish Her Royal Highness The Princess of Wales a speedy recovery from her surgery."