When John Moransits down to watch an old documentary on Christmas Day, he'll recognise one young boy.
As the black-and-white film rolls, a schoolboy looks out earnestly from the screen as he answers some question on Catholic doctrine in a Dublin school. It is nearly four decades after the filming, and I am watching it for the first time in the darkened auditorium of the Irish Film Institute in Temple Bar. I take a particular interest in the boy and his classmates, all of whom I once knew well.
"Because of Adam's sin," he says, "we are born without sanctifying grace. Our intellect is darkened, our will is weakened, our passions incline us to evil and we are subject to suffering and death."
As he sits down, I whisper to my friend, "That was me!" She smiles, "I know".
Strong emotions and old forgotten feelings percolate and surge as I merge into the unfolding footage of Dublin in the 1960s, which was captured in Rocky Road to Dublin, a documentary directed by Peter Lennon in 1967 and which will be shown this Christmas Day.
As the film played, I was lost in reverie: back in "Synger" with all the boys. At the Grand Canal locks below Leeson Street Bridge there are young swimmers, where I swam too. I'm in the eye of the camera as it pans up Charlotte Street towards Charlemont Street and then takes in the grand Georgian sweep of Harcourt Street, past the famous Five Club, which was to Dublin in the day what the Cavern was to Liverpool.
Soon I would be a self-conscious shaper in the Five, and less than a decade later I did the O'Donoghue's thing in Merrion Row, trying not to lose an eye playing bodhrán beside the wayward bow of an old fiddler, the late Hughie McCormick, whose ghost flickers in the excellent footage shot there.
My little cameo in Rocky Road began one day when a small film crew arrived in our classroom in Synge St CBS. It was led by Peter Lennon, who had been a pupil in the same classroom some 15 years previously and was now based in Paris.
Our class had recently been Confirmed, so the Catechism answers were fairly fresh in our minds. For us, the occasion was a marvellous distraction, but ended all too soon, and we reluctantly returned to the mysterious pleasures of algebra, geometry and the modh coinníollach.
After the documentary was completed, Peter Lennon and Rocky Road, featuring a clip of me, turned up on the Late Late Show. Some controversy seems to have surrounded the event, allegedly involving a barb from the rapier tongue of Ulick O'Connor, the elegant Eamon Dunphy prototype. (Alas, RTÉ has lost the tape.)
What I didn't know until four decades later was that the next year, in 1968, our little film turned up at the Cannes Film Festival, where it brought the house down. Immediately after it was screened, Jean-Luc Godard, François Truffaut and a group of delinquent intellectuals demanded the festival be shut down in support of students who were revolting throughout that long hot summer of '68.
Peter Lennon says the students were so taken with Rocky Road they brought it from Cannes and smuggled it through the acrid, smoke-filled streets of a disturbed Paris to the hallowed halls of the Sorbonne, into which swirling riot gas from the contested streets outside seeped intoxicatingly.
Meanwhile, back in Portobello, as Paris was burning, the times were a-changing too. After school, if in the mood, I donned my denim waistcoat and bell-bottom jeans, each painted with psychedelic flowers, put flowers in my hair, and shuffled off on my daily newspaper round.
In the Television Club on Harcourt Street, before the afternoon was over on Sundays, my intriguing new passions were now inclining me to loiter in the vicinity of the lovely Joan Kelly so I could swoop for the last slow set, the infamous "lurch". Down in the Moulin Rouge Club on South Great Georges Street, our hormones percolated uncontrollably as an emerging young trouser-snake named Phil Lynott flung the mic about in joyous abandon. It was the best of times and it was the worst of times.
For those best of times, I am among many who owe director Peter Lennon a debt of gratitude for recalling those colourful, psychedelic days. And I thank him too for the timely delivery of my "15 minutes of fame" in the year Andy Warhol coined that ubiquitous phrase.
As for the worst of times? In a film on the making of Rocky Road, Lennon wondered wistfully after the Synge Street scene: "What will they grow up to be?"
Well, for a start, to the right of me in Rocky Road is John Riney, whose artist sister Imelda, her infant son Liam, and a priest, Fr Joe Walsh, would later be murdered in remote west Clare. For this reason, it is appropriate that Rocky Road is seen in black and white.
The Rocky Road to Dublin will be shown on RTÉ1 on Christmas Day at 7.30pm