Father Michael Cleary was one of the greatest communicators the Catholic Church in Ireland has known, a man who could reach out to young people in a unique manner, the epitome of a young person's priest.
He went around Ireland singing and playing the guitar. He chain-smoked and told slightly racy jokes about nuns. He put across the message that religion need not be staid, stuffy and pious.
"You can kiss a nun once, you can kiss a nun twice, but you mustn't get into the habit," he would quip during a clerical cabaret act, put on by himself and other priests for rapt audiences.
He was a Father Trendy, a showbiz cleric who lived in the real world.
He was on the same wavelength as the young: "He had charisma, he really connected with us," a former convent schoolgirl recalled.
The church in Ireland actively encouraged his approach, drafting him in as the warm-up man before Pope John Paul II's appearance on his 1979 visit to Ireland. He was favoured for one very specific reason: no matter how informal and even risque his delivery, his message was the same: that the Church's laws must be obeyed.
This was most of all the case, he stressed, in relation to sexual matters. Kids could have a bit of fun, but pre-marital sex, contraception and abortion were all strictly prohibited.
And priestly celibacy was an absolute given.
He drove this message home in his sermons, at his concerts, on his late-night radio phone-in show and in his newspaper columns. His value to the Catholic Church was that he projected its orthodox message of self-denial in an unorthodox way.
After years in the media limelight, Father Cleary died in 1993. But all Ireland is once again talking about him following a fascinating documentary that pictured him at home with his live-in lover and one of their two children.
The gap between what he preached and what he practised was incredible. Phyllis Hamilton was ostensibly his housekeeper but they were sexual partners, living in flagrant disregard of the solemn rules of the doctrines preached by his church in general and by himself in particular.
In his private life there was little in the way of self-restraint: it was a case of sex in the afternoon as a preliminary to an evening of preaching at teenagers to control their sexual stirrings.
The newly aired film footage shot by Alison Millar shows Cleary with his partner and their son at home together. With hindsight they clearly made up a family unit, yet Cleary was so confident he was immune to exposure that he allowed Millar to move into the home for several months.
His secret life was made possible by the fact that most in the Ireland of his day found it unimaginable to think that a priest could have a sex life.
Those who suspected anything kept their doubts to themselves, as was the custom. Cleary's son Ross, who appeared in the documentary, explained: "I think some people clicked and they kind of knew but would rather not know. No one would have thought he'd have the guts to hide it in plain sight like that."
The relationship between Cleary and Hamilton was not a partnership of equals. He was both one of Ireland's best-known priests and a media celebrity; she was a former psychiatric patient, taken into care at the age of 14 after abuse.
Yet they were together for 26 years. When they met he was in his 30s, she was still a teenager. She was vulnerable, flattered, in awe; he was manipulative, solemnly telling her they were married in the eyes of God. He insisted that their first child should be fostered.
Nor was he faithful. He was noted for taking care of unmarried mothers, and she once found him in bed with one.
It all came out only after his death from cancer. At first the church hotly denied the whole thing: when Phyllis Hamilton's psychiatrist confirmed the set-up he was denounced as not credible, not independent and antagonistic to the church.
This was partly because of the Cleary case, but also partly because the psychiatrist also remarked that he "could fill the newspapers for a month with similar stories I've had with patients and victims and problems with priests."
The doctor was borne out on both counts: in the Cleary instance by medical evidence and more generally by the sex scandals that caused severe damage to the church in the ensuing years.
In one ludicrous episode Cleary went privately to a bishop and confessed he had an irregular relationship and two sons. The bishop told him to clean up his act and Cleary went off, momentarily contrite.
Later Cleary was astonished to learn that Eamonn Casey, the bishop who chided him, himself had a secret son. Cleary had confided in the bishop but the bishop had not confided in him.
Ross Hamilton recalled how his parents reacted to the Casey revelations: "I remember my mum woke me up to tell me the story had broken. She was in a panic. What it meant was that the witch hunt was on. My father came back and the panic was on and it was the first time we had to sit and confront each other as father and son."
Cleary was to die soon afterwards, without publicly acknowledging that Phyllis Hamilton was his partner or that they had two sons. He died without providing either financially or emotionally for his family.
According to Ross Hamilton: "He was really terrified of his sisters finding out and people being disappointed and the family name being hurt. And to all intents and purposes he got away with it. He died. He didn't get caught. We dealt with the aftermath."
Hamilton has since led a troubled life, experiencing problems with drink and drugs, but he has won widespread admiration for his obvious determination to overcome his problems.
It was only in Cleary's final days that he acknowledged to Ross that he was his son: Phyllis had already told Ross who his father was.
Ross Hamilton had a private mantra from the age of 10: "He doesn't know that I know that he knows that I know," he would recite to himself.
"I never once called him Dad," Ross recalled. "It was always Father."
Phyllis died eight years after Cleary: according to Ross she became a hermit who slowly drank herself to death.
"All during the scandal I never thought to blame him," he recalled. "Then as I hit my early 20s, I thought: 'What a bastard'. But as I got older and thought about it more, I can put things in perspective.
"I still love him and I understand why he made his mistakes. I can forgive him now and understand how afraid he was of his own family finding out."
Cleary was obviously a complex character who managed to live a double life for decades.
"If you try to define what kind of man Michael Cleary was you are wasting your time," a friend remarked on the documentary. "It's like knitting with elastic."
Phyllis Hamilton's psychiatrist, who urged Cleary many times to end the relationship, said of him: "He simply couldn't face bringing those two sides of his life together.
He really loved Ross - that came over again and again - and he loved Phyllis.
"But he couldn't face that half of himself when he was out as a priest."
After the film, some have argued that Cleary deserves more sympathy than has been extended to him and that perhaps he should be regarded more as a victim of the Vatican's unyielding line on celibacy.
And after all, it is said, however shockingly he behaved, his transgressions pale into insignificance with what has come out concerning serial child sexual abuse.
Yet he does not escape all responsibility there. Respected investigative journalist Mary Raftery has detailed how he reacted when a family called him in after a priest abused their 13-year-old son.
Cleary in essence told him to get over it, a response that was pretty much par for the course for the church in those days. The priest went on to abuse a dozen more children.
Since Cleary died, the status and power of the church in Ireland has plummeted to an extraordinary extent due to Cleary and all the other scandals.
The film-makers took Ross back to his father's former parish, where he was warmly welcomed by a group of women. One of them told him: "You're the image of your father, God bless you."
However, as one critic summed up, Cleary "wasn't half the man his son turned out to be".