King Charles and Queen Camilla surprised spa guests in their bathrobes in a "very surreal" meeting at the monarch's Poundbury eco-village.
The royals shook hands with them outside the Monart Spa as well as greeting many of the hundreds of well-wishers who had gathered to see them.
During the encounter the King smiled and joked with the pampered trio outside the spa in Queen Mother Square.
Speaking afterwards, Faye Harris, 34, a marketing director from Northamptonshire, spoke of her surprise at meeting the King and Queen during the spa day.
She said: “It was very surreal, and I did not expect to meet them this morning.
“We were aware the King and Queen were coming this morning when we first turned up and did not expect to see them.
“The manager came up and said they were likely to be here around midday and would we like to pop our heads out of the window, not shake his hand in our bathrobes.
“It was fantastic to meet them, very nice people.”
Ms Harris was enjoying the spa day as part of a week-long visit to her parents who live in Dorset.
The King and Queen were visiting Poundbury, built on Duchy of Cornwall land, to mark the completion of Queen Mother Square, the centre of the village.
To commemorate the visit, Poundbury development director Andrew Hamilton pulled back a curtain to unveil bronze reliefs of Their Majesties, which have been created by artist Ian Rank-Broadly,
As he revealed the sculptures in a gust of wind The King quipped: “It very nearly unveiled itself.”
They sit above a Portland stone plaque that records architects and businesses that worked with the Duchy to create the Queen Mother Square.
Charles, as Duke of Cornwall, ran the Duchy from 1969 until the death of the late Queen last year when he handed it over to the Prince of Wales.
It was the royal couple’s first visit to Poundbury, near Dorchester in Dorset since the Coronation.
During the visit, they officially opened The Duke of Edinburgh Garden which forms part of Pavilion Green.
They met with George Carter, the landscape designer, before listening to children from Damers First School perform their Coronation song Sing For The King.
The King and Queen thanked the children and also met the outgoing headteacher Catherine Smith.
Addressing the children, Charles said: “Thank you very much that was brilliant.”
They also toured the obelisk garden and were introduced to sculptor Frances Segelman, Lady Petchy, who created a bronze bust of The late duke of Edinburgh, which forms part of Pavilion Green.
Poundbury is an urban extension to the town of Dorchester and around 2,300 homes have been built so far, of which 35% are affordable housing.
The development is providing employment for more than 2,600 people working in 250 shops, cafes, offices and factories.
When completed in around 2028, Poundbury will have grown to 2,740 homes, increasing Dorchester’s population by 25%.
The estate prioritises people over cars and commercial buildings are mixed with residential areas, shops and leisure facilities to create a walkable community.
