Styles’ journey has been remarkable. Just 13 years ago, he was a cheeky teenager from a Cheshire village between Manchester and Stoke-on-Trent who went on X Factor for a lark and was very nearly sent home by Simon Cowell (and would have definitely received his marching orders had Louis Walsh had his way).

He had a chirruping charm – but his voice was underdeveloped, and, early on X Factor, he seemed unsure of himself. Nobody back then would have guessed they were watching a future pop titan.

Fast forward a decade and a bit, and Styles ticks off all the boxes demanded of a once-in-a-generation talent. He’s a style icon with a Gucci fashion line and a “gender neutral” cosmetics brand, and a pop star with 66 million monthly listens on Spotify. But he is also a Serious Artist whose music critics rave about in a way that Ed Sheeran’s output is not.

Consider the swooning response to last year’s Harry’s House LP, which the NME hailed as “a magical thing” and prompted Rolling Stone to herald Styles as “the Mick Jagger of our more enlightened age”. Nobody compares Ed Sheeran or Lewis Capaldi to Mick Jagger.

So how did he – and we – get here? Buckle up as we bring you the History of Harry in three chapters.

1: The Early Years

Styles was born on February 1, 1994 – the day Dookie by Green Day was released. When he was a child, his family moved to Holmes Chapel, a commuter town in Cheshire with a population of 5,500. His parents divorced when he was seven – though Styles says that his memories of the separation are vague and that he was not scarred by the news that his father was moving out.

“Honestly, when you’re that young, you can kind of block it out. … I can’t say that I remember the exact thing,” he told Rolling Stone. “I didn’t realise that was the case until just now. Yeah, I mean, I was seven. It’s one of those things. Feeling supported and loved by my parents never changed.”

He discovered music early, receiving the gift of a karaoke machine from his grandfather. The first song he performed, he says, was The Girl Of My Best Friend by Elvis Presley. His passion for pop was inherited from his mother, Anne, who listened to Shania Twain and Savage Garden. Meanwhile, his father, Desmond, was obsessed with Dark Side of the Moon by Pink Floyd.

Styles was told that he had a decent singing voice and, at secondary school, formed the band White Eskimo. “We wrote a couple of songs,” he said. “One was called Gone in a Week. It was about luggage. ‘I’ll be gone in a week or two/Trying to find myself someplace new/I don’t need any jackets or shoes/The only luggage I need is you.”

In 2010, when he was 16, X Factor was a juggernaut. It was suggested he try out when the auditions came to Manchester, and, for a lark, he gave it a go, with his mother and his older sister, Gemma, coming along for moral support. It was an uneven performance, and judge Louis Walsh told him he needed to improve his voice.

“Harry, for all the right reasons, I am going to say no,” said Walsh. But Cowell saw potential in Styles and felt Walsh had made the wrong call. “I actually don’t think they booed you loud enough there,” he told his fellow judge after Walsh had passed on Styles. And so, a little randomly, one of modern pop’s great rags-to-riches stories began.

2: One Direction

Styles didn’t dominate X Factor. He was set for the chop when Cowell had the idea of putting him together with four other also-rans, including a singer from Mullingar named Niall Horan. One Direction was born, and were a sensation from the outset. Matt Cardle may have won the competition in 2010, but by the time X Factor Live came to Dublin the following year, it was clear that the real stars were One Direction, their brief performance cheered on by a crowd that had come to see them and them alone.

One Direction was a boy band but with a difference. They weren’t choreographed to death, and their songs had a laid-back, almost lackadaisical quality. Not that there was anything tardy about their schedule – they released five albums in as many years and embarked on four world tours.

With Styles the de-facto frontman, they also did something that no other British boyband had managed in breaking America. Success in the US propelled them to 65 million album sales and saw the group unofficially crowned the world’s favourite pop group.

The schedule was punishing, and in early 2015, Zayn Malik quit. A few months later, Styles suggested to his remaining bandmates that they consider knocking it on the heads. And so, after an October 2015 farewell tour, they took their bows and went on indefinite hiatus. One Direction had by then long parted from Simon Cowell, as he observed with a trace of bitterness. “I hear so many things now, which they’re doing, which I’m not involved with. It’s a bit like I’m getting the hint you don’t want me to come to the party. Sorry for making you famous ….”

3: Harry Conquers the World

It’s not easy starting over after your boyband reaches the top. Just ask Gary Barlow, who, while in Take That, was feted as the new Elton John yet couldn’t get arrested as a solo artist.

Styles has made it look effortless with songs that draw on the California pop he soaked up from his parents as a kid in Cheshire. He also chose the perfect collaborator in Thomas Hull, aka Kid Harpoon. The two shared an immediate chemistry and Styles’s songwriting progressed in leaps and bounds.

Hull co-wrote Watermelon Sugar and As It Was and has also worked with Florence and the Machine and Maggie Rogers. He sees Style as belonging in his own category of mega-star and feels his journey as an artist is only beginning.

“When I look back at, you know, whether it’s Talking Heads or, Radiohead and even Tom Petty, those artists went on a run where they just knew they were in a creative stride and they just went for it. And that’s what I hope for going forward with Harry is that whatever it is next, let’s not try and second-guess it, or do anything based on what we’ve done before. Let’s just try and do something new and land somewhere exciting.”

Exciting is one word for the atmosphere that will fill Slane on Saturday. Styles, at 29, is unrecognisable from the curly-haired kid who walked in and sang for Cowell and Louis Walsh. But that bullet-proof charm endures – and expect to see it light up the County Meath venue this weekend.