By Colin Paterson
Entertainment reporter, BBC News
Proceeds will help to provide music education for underprivileged children
Pope Benedict XVI will be heard singing and speaking on an album to be released on the record label that was home to Nirvana and Guns N' Roses.
The pontiff is to release Alma Mater, an album of Lauretan litanies and prayers with musical accompaniment, through Geffen Records.
The label said listeners would be "shocked" by his "incredible voice".
The album, which features the Pope using five different languages, will be released on 30 November.
The project came about after the label learned earlier this year that Benedict XVI had been working on an album with the Choir of the Philharmonic Academy of Rome.
Colin Barlow, president of Geffen UK, explained: "We travelled to Rome, heard some of the music and realised it was a beautiful piece of music and something that actually could be an incredible record for us to work on.
"It's very much about delivering a really brilliant piece of music and making sure we treat it with the respect it deserves."
The album will contain eight pieces of music, one featuring Pope Benedict singing and the others providing accompaniment to his recitals of passages and prayers.
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In 1994, three Geffen acts - Nirvana, Beck and Counting Crows - occupied the top three in the US modern rock chart.
But Pope Benedict did not go into the studio - the Vatican supplied recordings of his vocals made at official services and also from speeches he made on his foreign trips.
The choir recorded their parts in St Peter's Basilica in Vatican City, while the Royal Philharmonic Orchestra recorded the classical backing track in London's Abbey Road Studios.
Barlow said the Pope was pleased with the progress of the recording.
"We've had a letter from the Vatican saying that he's heard the music so far and he's very happy with what he's heard," he added.
Proceeds will help to to providing music education for underprivileged children around the world.
Geffen Records was founded in 1980 and had its first number one album with John Lennon's Double Fantasy.
By the end of the decade it started to specialise in rock music, signing the likes of Guns N' Roses, Aerosmith and Nirvana.
Geffen also recently signed Dame Shirley Bassey.
The albums of Dame Shirley and the Pope will both be out in time for Christmas.
It is not the first time a Pope has released an album.
In 1982, John Paul II reached number 71 in the charts with The Pilgrim Pope, and, in 1994, his recording of The Rosary peaked at number 50.