For the past 17 years, Vicar Street, the Dublin music venue, has had its share of sell-out shows for superstar acts, among them Bob Dylan, Neil Young and Paul Simon. This week it set a record when the first show from its youngest ever headliner sold out.

The man in question is Al Porter, a young comic from Tallaght who performs there in March. Though only 21, Porter is not some social media-endorsed teen sensation but a curious throwback to a time when comics wore suits, had “engagements” rather than gigs, and received “notices” rather than reviews. Think Frankie Howerd delivering acidic, innuendo-laden commentary as he sits on the Luas Red Line and you’re on the right track.

“When Vicar Street told me I had created a new record for the venue by becoming their youngest ever headlining act, I thought Jesus, that’s awful,” says Porter. “When people see the word ‘young’ to describe a performer, they probably think it’s some naive young kid who has put up a few videos on YouTube and is the sort of show that’s only going to appeal to teenagers. But I’m an old soul; emotionally I’m already in my 60s.”

Second seller

Porter figured only his friends would turn up on the night. However with a second show now selling quickly, there may be plenty more engagements and notices.

“But seriously, being able to say you’re the youngest ever to do anything – that’s a bit of a s**t boast, isn’t it?” he says. “Then I was thinking of what Gore Vidal said to Truman Capote once about the problem of getting too much too young, and that worried me more. But then I just thought, f**k it, it’s a good tag line to put on the poster.”

Porter, less than two years into his comedy career, was first dazzled by the bright lights of show business while singing karaoke at Captain Americas in Tallaght. His closing number used to be There Are Worse Things I Could Do from Grease.

“I went from Captain Americas to a comedy night in a pub in Tallaght,” he says. “All I had ever known about comedy growing up was seeing the likes of Michael McIntyre, Lee Evans and Peter Kay on TV and I thought that was the sort of material you had to do in order to make it. But that local comedy night showed me that comedy could be about you and your world.”

Judicious filth

What distinguishes Porter from the pack is his immense likeability – when he hits his stride it’s like a really good pub conversation. There are judicious moments of pure filth in his set, alongside intimate details of quite a quixotic approach to his sex life. And there’s the old school appeal – triple entendres and knowing in-jokes that hark back to the days when an arched eyebrow could be a punchline in itself.

Porter was supposed to be a priest. “Well, the first plan was for me to be some sort of Billy Elliot dancer; when you’re from a working class area and you’re no good at sports, you get sent to dancing classes. But I was hopeless at that, so decided to become a priest because when I did the readings at Mass people told me I had a lovely voice.

“My mother talked me out of becoming a priest and persuaded me to study philosophy at Trinity. I didn’t stick with it, but I did discover sex when I was there – so that was something.”

AlreadyPorter is routinely – and a little lazily – described as “the new Graham Norton” and once, “the gay Billy Connolly”. He is gay and his material can be very sexually explicit, but “it’s a bit dense describing anyone as the ‘gay’ somebody else”, he says. “I can lay it on thick if I want, but it’s more about me being as candid as possible about my sex life.

“It’s different for my generation,” he says. “We talk about being gay and dating and sex in the classroom and all of that. We have come on a bit in that regard. But I’m still really interested in the mechanics of sex, and I like exploring the implications of sex and relationships. For example, I’ve just found out that sexual behaviour is inappropriate in the workplace.”

So what has Porter got in store for his March shows? “There’ll be a velour curtain and me talking about having a STD, but that’s only to start with . . . ”

Al Porter performs at Vicar Street, Dublin on March 6th and 21st