Great Scott, it’s the bloke from that show

Killian Scott learnt that he had become properly famous on an airplane. While waiting for a flight to London, he was approached by a fellow passenger – who recognised him from his role as Tommy in RTÉ's hugely popular crime series Love/Hate – and showered with all the right kind of ebullient praise.

“We got on the plane and this other guy comes barrelling down the aisle,” Scott says. “He says: ‘Didn’t spot you there. I think Tommy is fantastic. And if you need anything let me know.’ Ten minutes later the food and drinks trolley comes down. I get a Twix and a packet of Pringles. The attendant leans in and says: ‘Don’t you worry. That’s all been taken care of.’ ”

He cackles at the absurdity of it. “That’s my Jay-Z moment. He gets bottles of Cristal for free. I get a Twix. I’ve arrived.”

Indeed he has. A fine-boned Dubliner with good skin and an unstoppable line in confident chat, Scott has just finished shooting John Michael McDonagh's Calvary , follow-up to the same director's The Guard . When we last left Tommy in Love/Hate, the poor sod had just been beaten to within an inch of his sorry life, but Scott is happy to reveal that he will return for more violent shenanigans. For now, Scott enthusiasts can sate their addiction with their hero's performance in the excellent, ecstatically received Good Vibrations .

In Lisa Barros D’Sa and Glenn Leyburn’s study of Northern punk, Scott turns up as Ronnie Matthews, guitarist and vocalist with the well-remembered Rudi.

“When we were filming, Brian Young, Rudi’s original guitarist, was our adviser,” Scott says. “We asked if there was any chance to meet Ronnie. He was not interested. Brian was the only one we got to meet. You could make a film about those guys alone.”

So what became of Ronnie Matthews? “He became a builder. It’s curious playing a real guy. There are great expectations if you are playing somebody everyone knows. If they don’t know them, you have licence. There are one or two clips of Rudi playing. But there is not so much visual information.”

‘Twas far from Belfast punk that Killian Scott was raised. Dragged up in the hard alleyways of Sandymount, he is the son of Henry Murphy, a barrister and writer, and brother to the journalist Colin Murphy and TD Eoghan Murphy. Alert readers will, perusing that last sentence, have already pieced together a tasty piece of trivia concerning Mr Scott.

"Yeah, yeah. That's right," he says. "I am Killian Murphy. One day, I realised I needed a new name. I was doing Under Milk Wood and had 24 hours to come up with a new one. 'Scott' is a distant relation on my mother's side. I also changed the C to a K. I remember watching the MTV film awards and they announced 'Sillian Murphy'. I thought: that is never going to happen to me."

Like his Corkonian namesake, Scott also dabbled in a career in rock music. While studying philosophy and English at UCD, he played drums in a pretty decent band. But acting eventually took over and killed any ambitions to become the next John Bonham.

“We were called Rockwyler,” he says with a self-deprecating laugh. “But acting had entered my world through older brothers. It was a basic thing: all that just looks cool. I did a play in school. Then Dramsoc became the centre of my universe. I let myself down and missed a rehearsal with the band. They broke up a week later. I’d like to claim it was because they lost their backbeat. It actually transpired the lead singer had slept with a girl the lead guitarist was in love with.”

After college, Killian Scott (as he then wasn’t) wrote to every drama school in England. He got nowhere with Rada. The London Academy of Music and Dramatic Art rejected him twice. He eventually made it into the notoriously rigorous Drama Centre in north London. Dedicated to Stanislavksi’s Method, the college – attended by Michael Fassbender and Tom Hardy – is famous for encouraging its students to impersonate animals, relive past traumas and generally indulge in psychic self-mutilation.

“The training itself was tortuous. The schedule was impossible. You were being stretched in so many ways,” he says. “But one thing that was very important was that it helped me diminish my inhibitions.”

It is common for acting students to make their excuses and leave college when the first decent job comes along. Sure enough, having endured two years of method madness, Scott jumped at the opportunity to play Tommy in Love/Hate. A properly tough study of Dublin hoodlums, Stuart Carolan's series, first broadcast in 2010, has skewered audiences like few other recent Irish dramas. Last November, the first episode of series three – emerging in a world of multi-multi-channels – managed to pick up a stunning 35 per cent share of the available audience.

Did he have any sense he was dealing with a potential smash? “Not really,” he says. “The main thing that attracted me was that it would get me out of drama school. It was a real job with real actors. It was something I was actually going to get paid for.”

Digging around on social media, he must have got some sense of what excites people about Love/Hate . "Well, there's somebody on Twitter pretending to be me," he says. "I mean they are pretending to be me, not the character. I never trust my immediate reactions to things. I was really pissed off. This person is just a fan. One night, I sat down and wrote a quite colourful tweet – I was quite drunk – but I didn't send it. Now I am trying to officially get that wiped. There was a Facebook page set up saying 'get well soon, Tommy' when he was in a coma. Ha ha! That's all part of the gig."

There are, indeed, worse things. Scott seems positively ebullient about the future. Before Christmas, he finished shooting Calvary , an experience he describes as a "very significant moment". He looks to be in the game for the long run. Supremely confident, good looking, well spoken, Scott shouldn't have to pay for his own Twix any time soon. "Yeah, yeah. I am trundling in a good direction. I am curious to see how things will work out before I take myself off the tracks."

Good Vibrations is on general release