Father Eugene O’Hagen, 48, his brother Martin, 45, and their old school friend David Delargy, 44, who all hold parishes in the diocese of Down and Connor, sealed the deal on the steps of London’s Westminster cathedral.
The singing trio, known as the Priests, said they would give the money they make to charity.
The group has a special exemption in their contract that allows them to break off from promotional duties to deal with parish work.
The three realised their musical prowess at St MacNissi’s College, Co Antrim, where they were nicknamed “Holy Holy Holy” due to their shared determination to enter the priesthood.
Fr Eugene, of the parish of Ballyclare and Ballygowan, said that what had happened may be “God’s design”. He described the signing as “breathtaking”.
“There is a real feeling of excitement and apprehension,” he said.
Fr Martin, Cushendun parish, explained the reasoning behind the clause that allowed the priests to carry out their parish duties: “We are priests first and foremost. Our work will be at the heart of our plans,” he said.
Fr David, of Hannahstown parish, added: “Singing is very much what we do. This is bringing it to a wider audience. We are singing sacred music, continuing what we have always been doing.”
Asked about the priests’ musical leanings, Fr Eugene said: “We have very Catholic tastes,” adding that he liked the quartet Il Divo.
Fr David chipped in: “My first ever purchase was Blondie’s Parallel Lines.”
“I enjoy a bit of jazz,” said Fr Martin.
The priests’ forthcoming record, as yet unnamed, is planned for release in November.