Cheering schoolchildren waved Union flags as they welcomed the King and Queen on their first visit to Wales since the coronation.
Charles and Camilla arrived at Brecon Cathedral, where students from Priory Church in Wales Primary School gathered to greet them on Thursday morning.
The couple met dignitaries including First Minister Mark Drakeford outside the cathedral, which was built in the 12th century and is set in the only walled cathedral close in Wales.
They were seated for a performance of Benedictus from Rod Paton’s Ascension Jazzmas, performed by Erin Thomas, 18, and the Brecon Choir Festival.
Dr Paul Shackerley, Dean of Brecon, led prayers including a blessing for the royal family.
Following the service, Charles and Camilla walked down the side of the church and met members of the congregation.
Melissa Davies, 35, was at the cathedral with son Rupert, aged 13 months, as her husband James was singing with the choir.
She spoke to the King and Queen, who both smiled and interacted with Rupert, who was sitting in his pushchair.
Mrs Davies later said: “The King mentioned the music and how lovely it was. I said my husband was singing in the choir, he asked if he was roping me in for the choir festival.
“It was such an honour to meet them, I couldn’t believe it. To have that memory for Rupert, with him being so young, is such a special thing for us.
“King Charles was absolutely beaming at him. He seemed so genuine. They were very happy to be here, you could tell.”
As Charles spoke to Mrs Davies, Camilla entertained Rupert by shaking his Paddington Bear toy.
Mrs Davies, from Newport, added: “You can tell that she is a grandmother, she obviously loves children.”
The visit by Charles and Camilla to Brecon was marked by a 21 royal salute by reservists from 104 Regiment Royal Artillery, the first of its kind to happen in Brecon.
It coincided with the first day of the Brecon Choir Festival, which is run by a team of volunteers passionate about Welsh choir and choral singing.
Miss Thomas, from Cardiff, said it was an honour to sing for the King and Queen and to talk to them after her performance.
“They congratulated me for my singing,” the student, who won the Brecon Choir Festival’s Young Singer Award, said.
“They asked me about my future plans and how old I am. I told them I would be applying for music college this year and taking a year out.
“They asked me about what kind of singing I usually do, and what voice I am. I am a mezzo-soprano.”
Charles and Camilla were presented with posies as they left the cathedral, which they last visited in July 2012.
