Infant Hercules meets once a week for rehearsals at a pub in Stockton and performs regularly across Teesside, supported by the National Lottery.
Founder Mike McGrother said the Manchester performance will live long in his memory.
“After the dress rehearsal I asked who do we follow, only be told it was Sam Ryder and the cast of Jesus Christ Superstar,” he said.
“I just shook my head and wondered how we’d follow such a phenomenal vocalist.”
But McGrother said the former Eurovision singer was “kind and incredibly supportive” of the choir and the audience was on their feet waving their phones with their lights on.
“It was a truly magical night,” he said.
The performance will be shown on The National Lottery’s Big Night of Musicals on BBC One on Saturday night.