Normally, priests walking down the main road leading to St. Peter's Basilica are as common as tourists.
But these three are on their way to do something remarkable in the extreme: Cut the first-ever CD made in what is without a doubt the most beautiful recording studio in the world.
"Well, here we are in the Capella Giulia," says Father David. "What a place!"
Fathers Eugene and Martin O'Hagan are brothers. They began singing with Father David Delargy when the three were schoolboys. Over the years the trio occasionally thought about making some kind of CD for posterity.
Instead, they've just signed a $1.5 million recording deal to sing songs from the Latin mass they so love, with contract clauses that must be unique in the music business.
The day job, Father Martin says, comes first:
"So being parish priests in the parish is actually our priority, and we have asked that that be put in the contract, and that was actually done."
It means that parish duties, like weddings and funerals, come before record-promoting obligations (like interviews).
"We're very busy," O'Hagan said.
And what about the money, Father Delargy was asked?
"Obviously as priests we are constantly preaching, you know, from Sunday to Sunday about the obligation to charity, to love our neighbor and, you know, to think about those less fortunate than yourself, so I mean as Sony recording artists we're not going to leave that gospel aside."
Most of their repertoire is what the three call "uplifting" music, and while the singing priests achieved minor fame quite quickly, the elderly ladies of their congregations make sure they kept it in perspective.
"They were wondering who was going to be celebrating mass that morning," Father Martin recalled. "One wee lady turned around to the next and said, 'I wonder, is Frank Sinatra on this morning?' So, that maybe sums it all up."
But in the decades of violence known as the Troubles, being a Catholic priest in Northern Ireland had as many moments of horror as it did humor.
A few weeks after he took over his first parish, Father Martin had to give last rights to a shooting victim:
"I can still hear him in my own mind, breathing, trying to cling to life. I didn't realize just how badly shot he was at that time. This is my very first experience of administering the sacrament to someone in this context. To be very honest with you, I forgot the words because I was so shocked by what I saw."
His brother Eugene's baptism of fire came when he had to bury a man who blew himself up trying to plant a bomb.
"Very difficult situation to deal with," he said, "commending them to God's mercy, etc., but not in any way condoning what they set out to do."
Being a priest offered little protection.
"I was driving down into Belfast," recalled Father David, "and somebody stopped me in the car and put a gun to my head. They were trying to take the car from me, to hijack the car."
And so it was music, as much as faith, that helped soothe troubled souls, although turning professional also came with a steep (albeit less dangerous) learning curve.
"It was a bit difficult at the start," said Father David. "We spent a couple of sessions just, you know, jamming, for no better word."
And then there was the technology, like using earphones to hear the music.
"We had the orchestra coming in through one ear and we had to leave the other ear free so we could relate to what each other was doing," said Father David. "It was a bit difficult at the start."
And that pales next to the problem of wiring up a 54-voice choir in a chapel that dates back to 1506, has the remains of a fourth century saint beneath its altar, and is decorated with artwork no recording contract could ever hope to pay for if it were damaged during the three days it took to record the CD.
In fact, the easiest element to deal with are the singers, according to co-producer Sally Herbert, who has spent most of her career dealing with rock stars.
"I mean, they're a lot calmer," she told Pizzey. "There's no temper tantrums, there's not many arguments.
"Their conversation is a bit different, you know," Herbert added. "In the vocal booth they're talking about which funeral they're going to be looking after later that day rather than which groupie they might have! There's not so much boozing."
[But we all know what fame can do.]
We asked, you often hear of rock bands practically coming to blows in the studio; do you have disagreements in the studio?
"That hasn't happened yet," said Father David. "Although there's no guarantee that it won't happen further down the line, you know?"
Given the kind of music they make together, somehow that seems most unlikely.
For more information visit the RCA Records Web site for The Priests.