The choir from North Wales wowed the judging panel
Their performance left Cowell, David Walliams, Amanda Holden and Alesha Dixon open-mouthed as they gave a beautiful and rousing rendition of Benedictus.
One young member of the choir told touchingly in the backstage interview that joining the choir helped him get over the death of his father.
He said: “It was like an escape and distracted me and helped me not to feel sad or worry all the time. When I am singing I don’t think.
“It’s lovely to perform with everybody as well.”
Roberts added: “There’s a real sense of community when we sing as a choir.”
Roberts founded Ysgol Glanaethwy performing arts school in Bangor with his wife Rhian