The Prince of Wales and the Queen of Spain joined together in their shared love of art to open a new gallery which forms part of a regeneration programme in Bishop Auckland.
Prince Charles and Queen Letizia, 49, first visited Auckland Castle in County Durham, one of Europe's best-preserved bishop's palaces.
It is at the centre of the Auckland Project, founded by Jonathan Ruffer and his wife Jane, hoping bring tourism to Bishop Auckland by using art, faith and heritage.
Queen Letizia, who has raised the profile of Spanish cultural projects worldwide in recent years, arrived in an Audi A6 with the registration plate SPAIN.
Charles, 73, kissed her on both cheeks and kissed her hand as he welcomed her to the castle where they viewed the Francisco de Zurbaran collection.
The Auckland Project also invited them both to open the new Spanish Gallery. School children waited outside waving flags of Spain and the United Kingdom and cheered as the royal party came out.
The gallery in Bishop Auckland town centre is the only space in the UK dedicated to Spanish art. The Queen and the Prince viewed paintings including The Holy Family by El Greco and Cherubs Scattering Flowers by Bartolome Esteban Murillo.
It was the Queen's first visit to Bishop Auckland, although Prince Charles has been before.
Auckland Project volunteer Ann Turnbull, from Crook, County Durham, shook the Queen's hand.
She said: "I thought she was wonderful, very classy, beautiful. I said 'welcome to Bishop Auckland' and she said the gallery was wonderful."
Rafa de Miguel, a London-based reporter for El Pais newspaper who covered the royal visit as part of a large Spanish media contingent, said: "It is very impressive. The whole exhibition is wonderful, with great taste the way they presented it."
On his visit to County Durham, the Prince of Wales stopped at Darlington to officially open the Darlington Farmer's Auction Mart as well. He sat down with group of farmers to hear about the challenges they face as energy and fertiliser prices rise.
The Prince also visited Sedgefield's NetPark to see the technological innovation at Kromek.
Experts there showed him how they are becoming a world leader in breast imaging technology for the early detection of cancers and in producing sensitive radiation detectors – to keep people safe from nuclear threats.