The fire in the upstairs lounge of Dublin's Westbury Hotel swelters, determinedly, as if it were Christmas Day, only we are a full month removed at this stage.

Outside, darkness falls around four o'clock as the dying days of January do their never-ending, soul-sapping thing. Inside, an array of journalists and broadcasters, armed to the teeth with expensive portable recorders, heavy-duty cameras and lighting rigs that could support a short film mill about, patiently waiting on their appointment. The man of the hour, the source of this controlled consternation, goes by the name of Niall Horan. JOE passes him in a hallway at one point, smile and nod exchanged, the face of someone with the guts of a busy day still in front of him. We're one of 18 interviews - be it print, online, radio or video - on the schedule. Trips home can go either way for any of us at the best of times, but this must feel like an endurance test, even if it is part of the job spec for any bona fide pop superstar in 2020. Away from the fire, finally, and into a pristine conference room. Horan, sporting a white checkered shirt, smart slacks and dress shoes, takes the opportunity for a quick breather. Minutes later, he's mic'ed up, settled down, ready to go another round. The general word on the street is that Horan, 26 years old and a decade on from breaking through via a reality TV conveyer belt, becoming a near-instantaneous household name in the process as one-fifth of One Direction, has handled growing up in the public eye and the pressure that comes with increasingly intense para-social demands quite well. You may baulk at suggestion of sympathy for a photogenic, talented musician with a reported net worth somewhere around the $70 million mark, but you tend to have to close the door on a regular type life somewhere along the way. To do so before you've reached adulthood is likely a tricky balancing act. "There's a very big Irish-ness to it," he suggests regarding the whole 'staying grounded' aspect of his personality. "We were all brought up in a certain way, to not be any way big-headed or anything like that. Even the places where we grew up - you'd stand out like a sore thumb if you thought you were in any way special. "The madness has happened around me and I've been the same fella, I suppose." He agrees that the mania gives way to its own odd regularity, that this is just his life. He talks about trying to establish 'Work Niall' as some sort of separate entity. Walking down a street or lounging in a pub for too long can often result in what he refers to as "abnormalities" once people inevitably clock the familiar stranger in their orbit. Mostly, he gets on with it; taking public transport, doing his shopping, practicing impressions, keeping himself out of trouble, the usual. Work brings out a "different character" that has managed to emerge in its own right following the indefinite hiatus of One Direction, more or less in effect since New Year's Eve 2015. Since then, all five members - Horan, Harry Styles, Zayn Malik, Liam Payne and Louis Tomlinson, respectively - have ventured down the path marked 'solo artist' to varying degrees of success. Styles has enjoyed a vivid metamorphosis into a socially conscious champion of young women and the LGBTQI+ community, his colourful throwback showman schtick attracting ringing endorsement from the likes of Fleetwood Mac icon Stevie Nicks. Malik opted for an edgy Frank Ocean-esque twist on pop with flat enough results, while Payne's desperate dive into club-hopping lothario who needs you to know precisely how much sex he's having suggests that we learned nothing as a society from the worst excesses of turn-of-the-millennium Robbie Williams. Louis Tomlinson, meanwhile, comes across like a nice enough chap. Horan seems to occupy his own space, which suits just fine. One Direction will forever be hyperlinked to his name but he's clearly more concerned with writing a decent guitar line than providing gutter press with easy column inches. Sure, he's dated or been linked to individuals that boast their own dedicated fan bases and he's friends - sorry, best friends - with Lewis Capaldi, but that registers as a natural reflection of his world. "He’s a funny man, very naturally funny," Horan offers of his Scottish counterpart. "People always say, ‘Is he actually like that?’ Yes. He’s actually probably worse. He’s probably worse on Instagram than he is in real life. He’s a very funny man and it just works so well. He’s the guy with the sad songs and then he’s the funniest guy in the world, too." An elevator pitch for Horan is less easy to lay down. In conversation, he's both friendly and endearingly anxious, conjuring up an introvert who plays extrovert on a nightly basis, thousands of screaming fans hanging on all words and movements. The boy band game, particularly in a live setting, affords individual attributes to become scripted signature flourishes. In the case of Horan and his 1D days, he emerged as The Sensitive One With The Acoustic Guitar, the brief spotlight in the set list a glimmer of what was to eventually come. Or, if you prefer, a Flicker. 2017 saw the arrival of his debut album, itself mostly characterised by straightforward enough singer-songwriter conceits. Horan, one of many writers in the mix throughout, was clearly keen to prove himself. The results varied, though languid outlier 'Slow Hands' revealed itself as a rather glorious bit of business, embracing a bright future with a respectful nod to the past.

"I love songwriting," he nods, reflecting on that first proper solo shot in anger.

"I feel like over the years I’ve gotten better at it. I’ve been lucky enough to work with some of the greatest songwriters and producers of our generation, learning off them every day and just really thinking about songwriting more than I probably used to.

"Especially now, because if I’m a solo artist and I want to put out music I just can’t release other people’s songs. I’ve been offered songs but there’s no point in releasing a hit song that you have to go into an interview trying to explain and it doesn’t come from you. You’d see it all over people’s faces. I wouldn’t be able to do it. That’s why a lot of my music is guitar-based. I’m no rebel to pop music or whatever but I do try to put my own spin on it.

"Obviously right now it’s very much a hip-hop/R’n’B-prominent scene, which is great. It’s the same with anything; it has cycles. Things come back around. Pop was big six or seven years ago and now R’n’B is having its time. It will probably be rock next and we’ll be back into the emo influence and it’ll be great - My Chemical Romance making a resurgence…"

Let's stop him there for just a second. Was young Niall Horan an emo kid?

"I didn’t look like one, but I was madly into the tunes," he smiles.

"Yeah, I was, definitely. Yeah, and it kind of goes in cycles; there could have been a very on-the-nose way of me going for this but I was like, I can’t, I just can’t do it. I have to do it my way. That’s why the hit I did have in ‘Slow Hands’, it kind of stood out because it was so different to everything else; it was basically an ‘80s jam with a pop twinge to it. That stood out in a very R’n’B hip-hop chart, I suppose."

New album Heartbreak Weather expands on a more buoyant palette via efforts like strutting lead single 'Nice to Meet Ya' and a sun-kissed title track. There's plenty of room for sensitive introspection, too, of course, hewn by raw life experience, determined to draw a positive.

"I went through a break-up there last year or the year before but I didn’t want to dwell on it too long," Horan notes.

"I’ve been through break-ups before where it’s dragging you down for such a long time. So, in terms of the songs, I wanted to make them up-tempo and maybe if they were sad songs I could kind of dress them up and be happy about it. I tried to just go and not… the last time I just sat there and everything was like six-eight and strummy and picky and very Damien Rice and people like that, that I love.

"That was the way I wanted to announce myself onto the scene," he continues.

"Now that I’ve done that and I’ve toured a bit, I’d seen a bit more of the world, I know what the fans are looking for from me now. Having spent all that time onstage, you get to see their faces every night of the week and know what they crave. I feel like I just needed a bit more energy in the music.

"Some people, friends of mine or whatever, would say, ‘My favourite part of the show was this song…’ and it would be something up-tempo that really raises the roof towards the end of the show. So I just felt like - I love live music, I love doing live gigs with a bit more tempo and in addition to the sad stuff, it’ll be a nice little blend for when I go on tour again.

"I felt happier in 2019. You know when you’re 25, over that brow of the early twenties thing. It just kind of felt different for some reason. I don’t even know why."

Turn the clock back a little. Let's say X Factor never happens. None of this happens for Niall Horan. What's he doing in 2020?

"God almighty," he exhales.

"I probably would have gone to college at some point so I would have liked to have gone somewhere in Dublin; UCD or DCU or something like that. I don’t know what I would have done because I was still at that period where all I wanted to do was be a singer. But was that going to happen? I also didn’t really know what - I was like 15, 16 and still going to the career guidance teacher to see what she thought of it and all that stuff.

"I don’t know. I would have loved to have gone to college off the back of that; absolutely no idea, coming out of college, getting my first job probably by now I would have thought so. Just like any other 25, 26-year-old Irish person, I would have thought."

One that busks regularly on Grafton Street, presumably.

"100%. There’s no doubt about it, I would have been busking on Grafton Street. It would have been me and Dermot Kennedy fighting for spots on the top of Stephen’s Green."

Who might win such a brawl?

"He looks like he’s hard as nails," Horan contends. "He wears quite baggy clothes and he’s got proper shoulders on him even in that stuff. I haven’t met Dermot yet - and please don’t take that the wrong way, I am not fighting Dermot Kennedy."

We won't book the 3Arena just yet, so. On the subject of Dermot Kennedy, himself enjoying his own moment in the sun as a more wounded, bombastic brand of troubadour, Horan reckons that he's one of the two most exciting souls in all of music right about now. "I can’t wait to see what Dermot does next, no joke," he says. "I’m not just saying that because we’re in Ireland. I honestly think that Dermot is the most exciting thing because he dresses different, his voice - you do not expect that voice to come out of that body, his songs are incredible, his album is going really well and I can’t wait to see what happens in the States for him.

"And then there’s… I think Billie Eilish is the number one. She’s even making me think that stuff I didn’t think I could do, I can do now. I was always told in songwriting rooms - well, not always told, the odd person would say, ‘Oh, your melodies are quite jazzy and bluesy and not straight down-the-middle pop stuff’ but some of hers aren’t, either.

"She’s managed to construct, her and her brother construct the production around the way she sings that makes it just fit into loads of different… if I asked you what kind of music Billie Eilish does, you wouldn’t be able to tell me because you can’t really stick her in one little spot."

Gun to the head, I'd go for 'ASMR pop'...

"ASMR pop!" he laughs. "Because of the whisper, because she nearly whispers. There you go, it’s right there.

"Usually, to be right in someone’s ear, you have to sing it really loud but she’s done a really good job of it and she’s made me think, proper. Now when I sit down to write a song I try and think like I think she thinks."

There's a nice dovetail in that, given that Horan has undoubtedly inspired a few young women the world over to pick up a guitar and learn the craft. Put this notion to him and there's mild surprise in his response, though he's surely well aware.

"I do see people doing covers, or you hear people saying, ‘I took up guitar because of you’ which is pretty incredible for a fella that can’t really play the guitar that well," he considers.

"It’s crazy, the relationship that you end up having. There’s no way when we were young that celebrities or whatever you want to call them were as accessible as they are now and I think that’s the thing about social media, it’s probably the greatest thing about it; that things like that can so tangible and feasible and it can actually happen.

"Just chatting away - which I am - just chatting away to normal people, it’s cool if they pick up a guitar off the back of me doing it, or they take up songwriting. I get asked a lot about songwriting and I try to give them advice. Or they’ll be looking for new music from me, what I’m listening to myself. It’s quite a cool little relationship we have going on there. I don’t really think of it as like fan to artist, I just feel like I’m chatting away to some people online."

How long does he spend engaging with social media?

"I do a lot of them Instagram Q&A things. I’m on there quite a lot, maybe once a week I’ll do 10 or 15 questions and just chat away. On Twitter I’ll reply to maybe five or six tweets a day. You’re sitting on a train or sitting in the back of a car or sitting in an airport, I’ll just be tapping away."

There is a noise pollution danger for any celebrity with a major Twitter or Instagram following, however, not least when there are thousands of devoted fan accounts with your face on them, existing purely to track your every move. Overwhelming, right?

"Kind of," he accepts after a pause, choosing words carefully.

"I’ve noticed if I’ve phrased a tweet or something wrong, everyone is jumping on you. You can’t really retract it. You delete a tweet, they’re going, ‘Oh, what did you delete that for?’ - you do feel a pressure to make sure that you read back and proofread stuff, even if it’s just a four-word tweet.

"It gets quite intense on there really fast. That’s just the nature of the beast and that shit happens, I suppose."

Fans are fans, as he sagely accepts when musing on the sight of his own face tattooed on another person. He gets it, the well-meaning intensity, but maybe refrain from asking him to scrawl something down for the purposes of getting his handwriting inked forever. That one he finds a lot more difficult to comprehend. Time eventually ticks down, wrap-up signal aimed in our direction. The nature of the beast. Days like this can only really offer a glimpse of the human being behind the superstar. There's an unspoken contract to adhere to something of a script, hit promotional marks, don't dig too deep, cheers. Horan, seemingly affable by default, makes it easy while smartly keeping himself at a distance. His most interesting choices are still in front of him, you feel. Exiting, you pass an assistant locked into a phone call since you first encountered them on the way in. Horan asks if there's room for another quick break. Back in the makeshift court, a fresh round of eager faces assembled, the fire burns bright still.