The Prince of Wales and The Duchess of Cornwall visited Northern Ireland today.
The Priests, an unusual singing sensation, put on a special performance for Their Royal Highnesses in the unlikely venue of a community centre in the County Antrim town of Ballyclare.
The Prince and The Duchess were clearly delighted when they were serenaded by the group - Father Eugene O'Hagan, his brother Father Martin and school friend Father David Delargy – and happily accepted an autographed copy of their million-selling CD.
Formally opening the Ballyclare Concerns Centre, The Prince thanked everyone for their warm welcome and said The Priests' singing had been "a particular treat".
He said he was "enormously" touched by their choice of music, Benedictus by Welsh composer Karl Jenkins which was followed by an Irish Blessing.
The Prince roared with laughter when they presented him with their CD, telling him it was from his one-time favourites The Three Degrees.
The Priests said they were thrilled to have sung for The Prince and The Duchess.
Father Eugene said: "This was our first royal command performance and we were very touched by The Prince's words.
"It was quite a humbling experience in many ways."
Father Eugene is parish priest in Ballyclare and his brother and school friend are priests in neighbouring County Antrim parishes.
He added: "It was a fantastic opportunity to meet Their Royal Highnesses and introduce our families and friends who travelled here especially today."
There was a double celebration for The Priests, as shortly before they sang for The Prince and The Duchess they were contacted by their record company and asked to select the content for a second album.
The unlikely trio have become international stars, with their album released in 32 countries, after it became the fastest selling classical album in UK history on release last November.
Several hundred people gathered in the freezing cold outside the community centre.
Their cheers and yells of "over here, over here," prompted The Prince to lead his wife away from the welcoming party and shake hands with many in the crowd.
Earlier The Prince and The Duchess rewarded a smaller, but no less enthusiastic crowd, in the seaside village of Glenarm on the County Antrim coast with an impromptu tour in defiance of the near-freezing conditions during which they visited the Glenarm Post Office and met retiring Postmaster William Pullins.
The Prince had discussions with members of the village committee and The Prince's Regeneration Trust about appropriate regeneration for the village.
He also met workers from the Glenarm Organic Salmon Farm which is still being restocked after jellyfish swept through the salmon cages 14 months ago, killing millions of fish.
Later during a visit to Belfast's Linen Hall Library, The Prince and The Duchess met young people who have been helped by The Prince's Trust in Northern Ireland.
Young entrepreneur Broderic Sloan made sure His Royal Highness left his last engagement in Northern Ireland not only with an uplifting story, but also with a business card.
Mr Sloan, 32, who had to learn to read and write again after suffering a serious brain injury in a horror car smash, set up his own plumbing firm in Islandmagee, Co Antrim with help from The Prince's Trust.
He was one of a number of inspirational young people who were introduced to the Prince and the Duchess of Cornwall at Belfast's Linen Hall library.
"I gave The Prince two business cards and The Duchess one, just in case," he joked afterwards.
"They were very easy to talk with. He said he was very happy to see I had been able to get my firm up and running and was doing well and that I was an inspiration to other young people in similar circumstances."
During the function The Prince talked of the pride he took in listening to stories of people who had been helped by The Trust.
"It always makes me unbelievably proud to hear about their successes and businesses, particularly when so many have had such a difficult time when they were young," he said.
"Any kind of horror may have happened to them, and that they have overcome these difficulties is really wonderful."
Earlier The Prince had taken a tour of the historic city centre library, which was founded in 1788.
The Prince was asked to sign two copies of the children's book, The Old Man of Lochnagar, that he wrote almost 30 years ago.
One will be kept in the library for posterity and the other auctioned off for charity.
The library holds some of the oldest and rarest books in the world and during their visit The Prince and The Duchess were given a special viewing of a few of its most treasured items, including Incunabulum - De Anima, by Avicenna, which was written in 1497.
The Duchess also took time to meet two of the library's younger members - 11-year-old Charis Saunders from Ballygowan, Co Down and Claire Arrell, who is 14, from Newtownabbey, Co Antrim.
"I was really nervous but she was really nice and made me feel at ease," said Charis afterwards.
Claire added: "It was really exciting, that was the first time I`ve ever met royalty."
On arrival The Prince and The Duchess were greeted by Lady Carswell OBE, Lord- Lieutenant of the County Borough of Belfast and went on to meet Ms Marney O'Neill OBE, President of the library's Board of Governors, and Mr John Killen, Acting Librarian, both of whom accompanied The Prince and The Duchess during the visit.