John's Boys Male Chorus received a standing ovation on the ITV hit show with their rendition of Harry Style's "Falling".
The 36-strong group even got Simon Cowell to his feet, who said their rendition was "quite beautiful".
While Alesha Dixon said the choir, which rehearses in a cow shed, gave a "beautiful performance".
However, Bruno Tonioli was moved to tears by the choir's performance, and told them: "I was in pieces. That is what perfection does to me. It was perfection, every aspect of that performance was perfect."
The choir's leader, Aled Philips who is director of music at Oswestry School, even quipped that host Ant McPartlin had been the inspiration for the choice of song - after the presenter slipped over on stage in a previous show.
The choir, based at Rhosllanerchrugog in Wrexham, is made up of teachers, traders and choir singers of all ages who have come together through their love of singing. The two youngest members of the choir are current pupils of Oswestry School – Dan and Akaash.
It was formed in 2016 when members collaborated to celebrate the lives of their former conductors, John Glyn-Williams and John Tudor-Davies.
Despite the judges singing the praises of the choir, the group failed to make it through to the final during Tuesday's semi-final.
Physical comic Viggo Venn won the audience vote and automatically made it through to Sunday's final, leaving John's Boys going head-to-head with eleven-year-old singer Olivia Lynes in the judges' vote.
The Welsh choir secured Bruno's vote, but the other three judges opted for young singer from Bath.
The Britain's Got Talent final is on ITV on Sunday, June 4 at 8pm.