The Britain's Got Talent judge insisted that the LP will not include throwaway "show tunes" and claimed that the Scottish singer was "blown away" by some of the tracks they picked to record.
"We're not going to throw out some souvenir album of show tunes which everyone expects," he told Extra.
"We went through about 350 to 400 songs to choose from. She was blown away by some of the song choices... She's going to surprise a lot of people with this record."
Boyle finished runner-up on this year's Britain's Got Talent, behind dance troupe Diversity.