The success has come as a shock to the 130 singers from the London suburb of Crouch End, who received session fees amounting to pounds 9,000 between them for the album, Cinema Choral Classics.
The men and women of the Crouch End Festival Chorus meet to sing every week at a local secondary school and in the 13 years since the choir was formed have built up a strong reputation, giving concerts at the Royal Festival Hall and the Barbican Centre.
But they have never had a week like this week. An album of choral music used in movies such as The Mission and The Omen, recorded at sessions over two years, went straight in at number 13 in Billboard's classical crossover chart. It also reached number 20 in the classical crossover charts here.
David Temple, the orchestra's conductor and co-founder, said yesterday: "It's wonderful news. I know people will look at our name and think that it's something dowdy and suburban, but we are one of London's best choirs. We have toyed with the idea of changing the name, but we decided to stick with it as it's where we come from.
"We haven't got any plans to tour America, but if the album keeps going up, then it would be rather nice to go over to the States."
At present, he said, the choir just gets paid session fees for its recordings, but he added: "In future we may think about a royalties deal."
He said all the members of the choir were amateurs. Their day jobs included psychotherapists, teachers, city workers, shopkeepers and factory workers.
The record's producer, James Fitzpatrick, of Silva Screen Records, said yesterday that when he first signed the choir, his managing director wanted them to change their name but they refused.
"In America the radio stations are more interested in the films like The Omen. They don't mind what the name of the choir is."