The priests, who all hold parishes in the Northern Ireland diocese of Down and Connor, sealed the deal by the steps of London's Westminster Cathedral.
The singing trio, known as The Priests, said they would give money they made from the music to charity.

Uniform population
The people of Bustuchin, Romania, have taken to wearing army uniforms after the mayor got them for nothing.
"I read in the paper that the army had thousands of unwanted uniforms that they were planning to burn and I asked if I could have them as people in this town do not have a lot of money", said Mayor Ioan Ciocea.
"I gave every family in the town men's and women's uniforms, and they modified the garments to fit children as well.''

Gun Gran
A teenager faces a charge of abusing his senile grandmother after making her wear a black mask and hold a handgun for a video he shot.
Police in Lake Worth, Florida said the 85-year-old woman threatens on the video to shoot "all the pigs".
Michael Alfinez ,18, was arrested after police discovered the video during a routine car check.

Vanishing trick
Police in the Congo arrested 13 suspected sorcerers accused of using black magic to "steal'' or "shrink'' men's penises.
"I'm tempted to say it's one huge joke,'' said police chief Jean-Dieudonne Oleko in the city of Kinshasa. "When you try to tell the 'victims' that their penises are still there, they tell you it's become tiny or that they've become impotent.''

Chicko-saurus
Chickens could be direct descendants of Tyrannosaurus Rex, King of the Dinosaurs.
Scientists said new research indicates close ties between the fearsome predator and humble chickens.

Taste code
Scientists have worked out the genetic code of the papaya and found the key to the exotic fruit's delicious flavour.
The papaya, cultivated in tropical and subtropical regions of the world, is one of the most nutritious fruits.
Papayas also produce papain, an enzyme used in brewing, meat tenderising, cosmetics and pharmaceuticals.