Sporting a brown mane and whiskers, Jack laughs heartily at how out of practice he is, and credits Druid artistic director Garry Hynes for her patience and general loveliness.

Still somehow boyish at 29, the Cork-born Dubliner is stepping back into the world of high-profile acting after a sabbatical of several years that saw him retreat from red-hot stardom.

Instead, he concentrated on Collapsing Horse, the now-defunct children’s theatre company he co-founded in 2012 with Trinity pals while studying philosophy and theology.

“I definitely peaked probably when I was about 17. That was when I was acting the most and was really in a good flow. Whereas now I’m like, ‘God, how do I say my lines, how do I move my body!’”

Gleeson needs no introduction but here’s one anyway. As diabolical Joffrey Baratheon, he was one of the front-and-centre stars of the world’s biggest television drama, Game of Thrones, when it premiered a decade ago.

Before he even reached his twenties, his face was implanted in the hearts and minds of millions upon millions of viewers who loved to hate the horrid child king responsible for happily lopping off Ned Stark’s head and terrorising Stark’s daughter Sansa.

Killed off in Season 4 in a particularly infamous scene dubbed “The Purple Wedding”, Joffrey was too indelible to the very fabric of the show to be forgotten during the remaining four seasons.

Jack was just 22 when his final episode aired in 2014. Citing a loss of appetite for the industry, he announced he would be retiring from acting in order to return to college life and pursue other interests.

Reading between the lines, there was a sense that the brilliant young actor had become overwhelmed by the size of the show and his new celebrity profile.

“I detested the superficial elevation and commodification of it all, juxtaposed with the grotesque self-involvement it would sometimes draw out in me,” he said in a scathing critique of celebrity culture during a 2014 Oxford Union address.

Neither he nor many of his co-stars in the Medieval fantasy epic could have foreseen just how wholesale its appeal would be, the water cooler moments it would burn into our collective cultural consciousness and the anticipation that would greet each episode.

Nor that he and the cast would no longer be able to venture out unrecognised.

“It happens very rarely that I come away from an interaction with someone who recognises me and I say, ‘oh, I wish that didn’t happen’,” he says. “When I’m on my own, it’s totally fine. It’s more when, say, you’re on a first date, or talking to a friend in a pub who’s just lost a family member, and someone comes over and takes you out of who you are in that interaction and makes you into something else.”

A first date with a rabid Game of Thrones fan doesn’t sound healthy, I chide.

“No, it’s quite easy to stay away from that,” Gleeson laughs, clarifying that fans intruding during dates is more the issue.

“Listen, the best counterargument is that all I wanted to do growing up was to act in a big film or a big TV show, and I achieved my utmost dream.

“I used to pray in Mass, saying, ‘Please, I want to be famous, I want to be successful, I want to act for people all around the world’. And I achieved that, so I never want to come across as ungrateful because that’s not it.

“I was also able to buy a house in Dublin with the money I earned from Game of Thrones. So, the positives massively outweigh the negatives. The only negatives are just now and again somebody probably has too much to drink in a pub and is a bit annoying, but there’s no negativity really from those fan interactions.”

All the same, he’s not complaining that some of the heat has gone out of Game of Thrones fever since its finale two years ago. While he still gets recognised, he says, it is good for it not to be on everyone’s lips.

“I feel like it was nice, me leaving the show when I did. It was pretty crazy, you know, it was so popular throughout. I feel like it took even a little bit of heat out of the attention, the fact that I wasn’t in it for Seasons 5, 6, 7, 8.

“It’s so long ago. We probably filmed the pilot in 2009. I feel like such a loser talking about it – I’m now just a washed-up child actor talking about the TV show I used to be on!”

Polite to a fault and lightning of wit, Gleeson is a great conversationalist with an instinct for deflating heavy topics with a well-aimed gag.

While performance is not in either of his parents’ blood, it runs through him and his two older sisters, Rachel and Emma, who, from a young age, attended local drama lessons in Ranelagh’s Independent Theatre Workshop. Rachel still works in stage and screen acting, while Emma is a writer and professional declutterer.

“We probably could have gone to karate or football or bridge,” Jack says, “but that was just what was going on in the community centre at that time, so we went and did performance. I don’t know exactly where it came from, maybe it was just chance.

“We all just loved it so much. And it was all we could do and think about, always doing little plays and short films.”

Child roles in big studio fare such as Reign of Fire (2002) and Batman Begins (2005) went alongside more local outings such as indie horror Shrooms (2007) and Pat Shortt’s sitcom Killinaskully.

The role of Joffrey came as a surprise after an audition that went well enough for him to assume that he couldn’t possibly have got the part.

Then the phone rang and nothing would be the same ever again.

“They probably could have gotten a hundred different actors to play this part,” Jack says. “It wasn’t that I was the best actor in Ireland. I think my success when I was younger also came from the fact that I looked a lot younger than I was. If they wanted an 11-year-old kid, they could either cast an 11-year-old kid or they could cast a 15- or 16-year-old young man who had more experience.

“I don’t think there are many actors who are born with a gift. Maybe, but I certainly wasn’t. I just got loads of opportunities because I had a certain look and had a slight advantage because I looked younger and had more experience.”

His family were on board from the get-go. While his mum may have had to close her eyes through parts of the notoriously graphic violence, his sisters were huge fans of the show.

“My parents were always just really supportive. It was only when the Game of Thrones contract came that they did sit me down and say, ‘OK, do you want to do this?’, because it was a six-year contract and I was 17 or something. They were like, it’s totally your decision. I really respected them for that. The amount of crappy plays they’ve probably sat through with either me or my sisters with the video recorder...”

He swings back and forth between London and Dublin for long stints. London, where he first moved six years ago, brings with it multiculturalism and a feeling of relaxation.

Dublin, meanwhile, is where his close friends and family are, as well as giving access to the sea and mountains, things he admits to taking for granted in his early years.

There are other things that Gleeson is learning to appreciate in his 30th year of life. Game of Thrones mania might not be bubbling but there is still enough of a smoulder to support a global industry for fandom. This provides a handy means of supporting himself, he explains.

“I do these appearances at Comic Cons and fan conventions,” he says. “I’ve had so many incredible experiences going all over the world, from Ecuador to Australia. I get to experience a new culture and meet all these people and it’s always just really fun.

“It’s a ridiculous job because it’s like I’m being paid to just be me and to sit and talk to people. I did struggle with that when I was younger. Why are people paying their hard-earned money to meet me? I just felt like I was swindling them.”

It sounds like he has been wrestling with some guilt about this, I say.

“I think I was guiltier in the past. Now, the more I’ve done them, I realise that it’s actually kind of patronising of me to say, ‘oh, actually you’re spending your money the wrong way’. People spend money in all kinds of ways. And when I go to these places, everybody’s there with a big smile on their face, they want to be there. It’s just a bit baffling to me.

“But screw the guilt! Total lucky f**ker! I couldn’t imagine an easier, more privileged job where also I can come out of it and maybe I made someone’s day. And it means that if acting jobs aren’t so forthcoming, I can still pay the bills through that basically.

“That’s what I’m still trying to teach myself – that it’s OK that I’m doing this, trying to see it through more like a positive lens and not through a cynical lens.

“Maybe in the past, because it was so intense, I probably lacked a bit of humility. I’m not sure.”

Last year, Gleeson turned up in Sarah Pascoe’s BBC sitcom Out of Her Mind. Falling back in love with acting has come after a period of soul-searching where he admits to struggling to reinvent himself.

He had wanted to carve out a space to discover new passions and goals. He was still in his early twenties after all, was financially secure, and had achieved his dream. But it turns out that his true calling was right back where he started out.

“There was a part of me thinking, ‘I’ll probably never have this time again to fully just follow all of my instincts and any wish or whim,’” he says.

“I wanted to respect that opportunity a bit, and then after four years of doing that, you come back to the centre and you think, ‘maybe I’d like a bit more direction or just a job really’.

“Now, I’ve come full circle, and what drives me is performance and acting, aside from general life things like friendship and love. Just trying to enjoy more the actual act of acting and moving people.

“And now I’ve achieved another dream of mine. If I could pick any job out of the sky, it would probably be something along the lines of playing Konstantin in The Seagull with Druid.”

Jack Gleeson is back. A jobbing actor attending Zoom auditions and sending in self tapes, he insists that his familiar face does not mean he can pick and choose his roles. The fan-convention appearances are useful but they might dry up one day. And when The Seagull’s sold-out run at Galway International Arts Festival ends, he will need to find more work wherever he can. He sounds energised by the prospect.

He even takes into consideration how his future life as an actor will sit with ambitions to settle down and start a family one day. “It’s not the easiest job if you want to be a dad or a mum, but that’s definitely a factor.

“I see my career in a different way now,” he says. “Now it’s more, does it pay the bills, is the job interesting and good for my career? But then I’ll do anything! If you’re asking me about big stuff, the bigness of things wouldn’t put me off, nor does the smallness of things.

“Is it liberating not to be chasing the Hollywood thing?” he wonders. “That’s what I tell myself, and then that neurotic part of my brain says, ‘no, you need to be James Bond or something’. I have to talk myself down from the ledge and be like, ‘no, you’ve been there, and it was great’.”

Druid’s production of Thomas Kilroy’s ‘The Seagull’ (after Chekhov) will be presented online as part of Galway International Arts Festival this September 5-12, following a sold-out run of live outdoor performances at Coole Park, Co Galway this August. Visit druid.ie or call 091 568 660 for details.