The King returned to Sandringham on Friday, ahead of his hospital treatment for an enlarged prostate next week.
Charles, 75, was seen travelling to his Norfolk estate after flying back with Queen Camilla, 76, from Scotland, where the couple have been residing since the start of the new year.
The King, who has cancelled engagements and been ordered to rest, will be admitted to hospital in the coming days for a corrective procedure for the benign condition.
It is understood that Charles was keen to share his diagnosis, in order to encourage other men who may be experiencing symptoms to get checked in line with health advice, a move which has been praised by charities.
One in every three men over the age of 50 will have symptoms of an enlarged prostate including needing to visit the toilet more frequently, with more urgency and have difficulty emptying their bladder.
An enlarged prostate does not usually pose a serious threat to health, and it is not cancer.
As Camilla visited an art gallery in Aberdeen on Thursday, she said her husband was "fine" and "looking forward to getting back to work".
The Queen will be in Swindon on Monday, where she where she will visit one of its oldest family-run businesses – Deacon & Son Jewellers – in Wiltshire.
Buckingham Palace's announcement about Charles' upcoming hospital procedure came just 90 minutes after Kensington Palace confirmed that the Princess of Wales is recuperating at The London Clinic following abdominal surgery.
The King's daughter-in-law, Kate, 42, is expected to remain in the private hospital for ten to 14 days, and it may be three months before she returns to public engagements.
The Prince of Wales was seen driving out of the hospital on Thursday after visiting his wife.
Prince William, 41, has also rescheduled his diary in order to care for Kate and the couple's three children, Prince George, ten, Princess Charlotte, eight, and Prince Louis, five.
Kate was last seen publicly on Christmas Day when the royals attended church in Sandringham.
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