It has been quite a year for Brian McFadden, perhaps the most momentous in his life to date. First he left Westlife, then his wife Kerry. In between, he recorded a solo album, grew a beard and changed his name from Bryan with a "y" to Brian with an "i". Tabloid revelations have been myriad, and he is now officially a Love Rat. Well, not according him - but more on that later. Best, perhaps, to start at the beginning.
The breaking point came, he says now, when it was decreed that Westlife would record a cover version of "Mandy". By this stage in their pop career, four years and nine number-one singles since forming in Dublin in 1999, the band's executive producer, Simon Cowell, had already got them to cover songs by Billy Joel and Cliff Richard, and so Barry Manilow seemed almost inevitable. Westlife's typically slick treatment of one of the world's more nauseating ballads - which they sang, like most of their songs, in five-part harmony with eyes tight shut to denote real feeling - effectively sealed their fate as a professional karaoke act whose longed for credibility would remain ever that: longed for. For McFadden, always the most idiosyncratic of the five, it represented a low point from which he would not return.
It is mid-August when I meet him, a good month and a bit before he ends his marriage, reputedly by telephone. He is in good spirits, polite and affable, exuding a curious mixture of humility and self-confidence. He has stopped shaving since leaving Westlife, and has lost a lot of weight. Where once was puppy fat there are now sharp angles. He has just discovered his hip bones, which peak over the top of his jeans. He is clearly proud of them.
"I feel fantastic," he says. "I was put on this diet by [TV dietician] Gillian McKeith, and I lost three stone in three months." He pats his stomach. "I love the new me, but if I told you I wasn't still dreaming of chips and ketchup, I'd be lying."
Being solo, he says, sitting on the roof terrace of his Chelsea hotel room, is like being reborn. At the mention of Westlife's dreariest karaoke moment, he shakes his head ruefully at the memory, reaches for the first of many cigarettes, and says this: "It was ... it was fucking 'Mandy'."
An awkward soundbite, perhaps, but one that nevertheless encapsulates his emotions rather succinctly. McFadden felt he had become a laughing stock, a pop puppet pushed too far. He wanted out and began, methodically, to plan his escape.
"That was definitely a turning point," f he says. "I've always been very proud of Westlife, and I still think that we never got the respect we deserved, but I was fucking ashamed of that song. From the second we went into the studio to record it, I lost all interest."
His final year in the group - that sold more records in Britain than any other boy band - was the most miserable of his life, and things came to a head in March 2004. Westlife called a press conference to announce that, yes, the rumours were true. After six wonderful years together, during which time they had amassed 12 UK number-one singles and sold 32 million records worldwide, Bryan (with a "y") McFadden was quitting. A thousand teenage hearts were temporarily crushed, and a hundred paparazzi caught the emotional farewell hugs that remaining members Kian Egan, Nicky Byrne, Shane Filan and Mark Feehily exchanged with their most valuable, and now departing, component.
McFadden may have shed tears on that day, but they were strictly of the crocodile variety. He was in fact overjoyed, finally free from the band he had grown to loathe. He tells me that he was sick of spending time away from his beloved wife and two daughters, Molly, three, and Lily Sue, 18 months, so much so that at the grand old age of 24 he was, preposterously, considering retirement.
"I had no plans to do a solo career at all," he says with a cigarette-puffing solemnity that suggests he is quite serious. "Absolutely none. I wanted to stay at home, be with the family, play golf ..."
But this, clearly, is nonsense. Famous since the age of 18, public life is all Brian McFadden knows. Here is a man who, at 21, got Hello! magazine to arrange, cater and take the photographs of his wedding to former Atomic Kitten member Kerry Katona while banning relatives from bringing cameras of their own.
"Think about it," he reasons. "Cousins we'd not seen in years suddenly get invited to the wedding of two people who have become very famous indeed. It would have been a pain in the arse posing for a million individual pictures, which I'm sure would have ended up being sold to the papers anyway. We refused to sign any autographs as well."
After their betrothal, McFadden's star rose while his wife's stalled. She had left her band to have McFadden's child and later to dabble in TV presenting, but it was only after she was crowned Queen of the Jungle on ITV 1's I'm a Celebrity Get Me Out of Here that she became a proper, Heat-endorsed celebrity. The couple then became so famous that, as McFadden readily admits, "we can't even take a shit without the papers writing about it".
While he complains, he is also helplessly drawn to the limelight. Within two weeks of ambling about the family house, he contacted Guy Chambers, former songwriting partner of Robbie Williams, and asked him whether he was up for a spot of collaboration. Within 21 days, they had produced enough material for an album that McFadden would call Irish Son. He tells me that it will surprise a lot of people. "It's really personal," he says.
I only realise just how personal it is when I finally receive a copy of it two months later. Irish Son, which for the most part sounds like his musical hero Bryan Adams, McFadden's voice all husky and rough around the edges, is a break-up record. Since our meeting back in August, his marriage soured irreconcilably, which fuelled the writing of more and more personal songs. While love gone bad has long been a key ingredient in pop music, the break-up album tends to come six months or a year down the line, usually after the artist in question has endured the pain of the divorce courts and crippling financial settlements. But McFadden's is still headline news, the wounds still fresh, which makes Irish Son at times uncomfortably candid. "Lose Lose Situation" - with the line, "You can never win with women / It's pointless to try" - bristles with marital rancour, while "Walking Disaster" suggests likewise. "Be True To Your Woman" begs the question: which woman? And then there is "Sorry Love Daddy", an acoustic lament to his daughters which he wrote just two days before the album had to be finalised, leaving time for only one recording of the vocal. In it he sings: "Unforeseen misery has come between your mummy and me / We can love you more now we're apart ... Some day you'll learn to understand this wasn't what I planned." The album finishes with "Almost Here", a duet with Australian singer Delta Goodrem, the woman with whom, the tabloids now tell us, McFadden is head over heels in love. His ex-wife, meanwhile, is very publicly devastated.
"I can't believe he ended it all with a phone call," she told the press recently. "It's just so shocking, one of the worst moments of my life. I loved Brian with all my heart. I still can't believe he has done this."
Suddenly, the McFaddens are the nation's favourite soap opera.
Brian MCFadden always wanted to be famous, though he was particularly ill suited to the neutered world of boys bands. True, he could hold a note and was sufficiently pretty, but he was also partial to a drink and a smoke, and revelled in the kind of wilful behaviour that easily shattered the PG certificate he was expected to live within.
The first time I met him was two years ago, during Westlife's sold-out European tour. The pressure was already mounting, despite the fact that "Mandy" was still a full 12 months away. This was McFadden in what has since been called his Fat Elvis period, his bulky, 15-stone frame poured into a tracksuit, with a towel wrapped, boxer-style, around his neck. He was hungover and suffering from flu. While the rest of the band were fulfilling promotional duties in another corner of Berlin's equivalent to Wembley Arena, McFadden was in the canteen eating crisps and popping antibiotics and talking about his wife's "massive breasts". He boasted to me about his alcohol intake, and had been drunk, he said, for three weeks solid, illustrating this fact by holding up four fingers of his right hand. "Nobody tells me what to do or how to behave," he said. "I'd like to see them try."
The rest of the band were used to McFadden's hedonistic tendencies. Just a few months earlier, at the Brit Awards, and drunk on champagne, he had initiated a fight with notorious UK garage act So Solid Crew; all two dozen of them. "A handful came f running towards me, so I just put my head down and went straight into them, punching. If 20 people come at you, you've got to go for at least a couple of the bastards, right?"
Reminded of those days when we meet in August, McFadden gives another of his rueful smiles, and lights a new cigarette from the embers of his previous one. "We argued all the time, me and the boys, but it was never really serious because we were such good friends. Still are, actually. I only acted up because the crowd liked me playing the clown. But that was then. I've no reason to play the clown any more. I suppose you could say I've grown up."
When I next speak to McFadden, it is late October. He is tired and guarded, and clearly exhausted from his trial by the media. Since news of his marriage split emerged, the singer has attempted to maintain a dignified silence. But in light of the repeated tabloid accusations of his callous treatment of Kerry, his poor, heartbroken wife, he now wants to give his side.
"Look, I never dumped her on the phone, of course I didn't," he says. He does concede, however, that their relationship came to a head during a phone conversation but, "we'd been having marital problems for a long time and I'd been very unhappy. Things just got worse and worse. She was doing a movie in Galway [Showbands] and I was promoting [his recent number-one single] 'Real To Me'. We hardly ever saw each other, we hardly even spoke, except about the kids. And when we did, we argued."
The pivotal moment came when he was in Sweden on promotional duties and she was at her mother's home. She asked him if he loved her. He told her that he didn't.
"I suppose it was a bit of a shock to her," he says, "but I'm sure, deep down, she felt the same. You know, for a long time now we've been happier when we are not together - which kind of says a lot, doesn't it?"
And so the suggestion that the split was sudden and unexpected is, he insists, entirely erroneous. "It wasn't supposed to be this way but it wasn't sudden at all. We've been having problems for ages, months and months. When I quit Westlife, I was hoping that things would improve between us, but they didn't. The more time we spent together, the more we argued. I didn't talk about it because I didn't want anybody to know. It was a private matter, after all. Nobody else discusses their marital problems with the rest of the world, do they? They don't tell everybody in the office how miserable they are, so why would anybody expect that of me?"
And what of the rumour that he is now dating Ms Goodrem? Here, his exasperation spirals. "Look, I mean - Jesus ... No, of course not. No. I have a lot of female friends, right, and obviously now that I'm single I'm going to be linked to any amount of women. Delta is a friend. Am I in a relationship with her? God, no. I'm still trying to get over a marriage, for fuck's sake ..."
He has moved out of the family home in Dublin, and now lives in hotels, keen to throw himself into work: "I've told my management that I don't want to have any time off. I want to be busier than I've ever been so I don't have to sit around idle just thinking about it. That was Kerry's problem. She sat around thinking about it, and that just hurts and hurts. I'd rather keep busy." But, he says, he continues to see his daughters as often as he can.
"It's difficult. Kerry and I talk every day because of the kids. Sometimes we are friendly, other times ... well, other times it's all screaming and shouting. Every day for me, right now, is different. I feel excited, sad, lonely and I feel in limbo. I had to change a lot of things recently in my personal life and my work life, and I'm doing this because I want to be happy. Thing is, I'm finding you can't do that without first going through a lot of pain. But if I get happiness in the long run, it'll be worth it."
The pop star with the soap-opera life takes a laboured breath.
"Yeah, it'll be worth it," he says.
'Irish Son' is released by Sony on 29 November