During A Voice of America international radio phone-in, broadcast from a station in Bray, Garth Brooks took a call from a 17-year-old Iranian fan. "Wow, I'm surprised that you're 17 years old and like my music," said Brooks. "But I'm even more surprised you're in Iran."

Many might think he got that the wrong way around. OK, it's kind of unusual for a US superstar to have fans in Iran. But somehow it is even more bizarre that teenagers, no matter where they are from, could be devoted to a stocky, balding, grey-haired country and western singer. I mean, he's not exactly a Spice Girl or an angst-ridden adolescent rocker.

And yet, the evidence is indisputable. When Brooks left the station after the broadcast, over 500 fans had gathered outside. There were wide-eyed children, doting parents, beaming grand-mothers. And a veritable horde of screaming teens.

The image-conscious singer was clearly taken by surprise. He later revealed that he was "actually very embarrassed because I hadn't dressed up for the radio." Sporting a hip-hop style baseball cap and black jumpsuit instead of his usual cartoon cowboy accessories, he nonetheless did the decent thing, climbing up onto the roof of his mini-bus with an acoustic guitar to deliver an impromptu performance. The response was more than ecstatic. The crowd joined in with gusto, reducing Brooks to tears. He loves his fans, and they love him. It's a perfect relationship.

Forget Dolly Parton's breasts. Put all thoughts of the ever-expanding Carter-Cash clan from your mind. To say Garth Brooks is the biggest thing in country music would be an understatement. He is actually the biggest selling solo-artist in US music history, outselling Springsteen, Madonna, Michael Jackson, Frank Sinatra and even Elvis Presley. He is second only to The Beatles in US domestic sales, where he has shifted over 62 million albums since his eponymous debut in 1989.

His current American tour, which began in March, was the biggest selling tour of that year and shows no sign of letting up until its provisional conclusion – in December 1998. It has proved so popular that Brooks has had to postpone his planned 1997 world tour to accommodate demand at home, with dates being added at every venue in every city he has visited. The only international concerts he was not prepared to defer were his May shows in Dublin...

Between May 16-18, Brooks performed for an astonishing 120,000 devoted Irish men, women, children and, yup, teenagers at Croke Park. That, as the promoter Jim Aiken was keen to point out, is approximately 1 in 30 residents in the republic. His concerts sold out in a matter of hours, quicker even than the 1985 or 1987 Croke Park shows by Ireland's favourite sons, U2, an act with whom Garth has more in common than just a taste for dubious cowboy hats.

In terms of sheer scale, Brooks' shows owe more to stadium rock than to country hoedowns: they are Nashville via Las Vegas on a Hollywood budget. A flying saucer rises from the middle of the stage to deliver the band, a huge video screen relays Garth's every expression, there are explosions, helicopters, 300 pounds of confetti and the kind of sound and lighting righ that could simluate a world war.

Brooks himself employs a radio mike, enabling him to roam about the hundreds of feet of extended walkways like some kind of jogging cowboy, in training for a showbiz marathon. He could certainly give Mick Jagger a run for his money. Meanwhile, his backing group perform burlesque rock 'n' roll routines that make the E Street band look like amateurs.

But while Brooks uses every trick in the rock star canon, at the heart of his show are simple country songs delivered with the kind of conviction and sincerity that would put Tony Blair to shame. There are ballads of domestic romance (in Brooks songs like 'Unanswered Prayers', the woman you love is usually your wife), mini-melodramas of worldly wisdom ('The Night I Called The Old Man Out'), humerous tales of the working life ('Much Too Young To Feel This Damn Old') and bar-room singalongs for the common man ('Friends in Low Places'). And there are tears. Dedicating 'If Tomorrow Never Comes' to his mother, who is unwell, his voice chokes and a close-up on the enormous screen reveals the tears welling in his eyes.

But then, it doesn't take much to reduce Garth to tears. I did it twice myself. The first time, I simply asked him about the health of this mother. I might as well have hit him with a sledgehammer. He gawped at me, his Adam's apple bobbing and his eyes rimmed with water.

"We'll see," he gulped. "She's a tough lady."

Later, I asked him about his emotions, and started him off again. "I have no control over my emotions at all. None," he confessed. "When I get choked up I'm really embarrassed about it. I'd like to be this macho dude but ever since I was a little kid that's how it's been. I get choked up pretty easily." His voice trembled and tears ran, as he explained that something as banal as seeing a little girl in the audience sitting on her daddy's shoulders could turn him to mush. "When you think you're the guy they came to see, that makes you feel proud and you know if your mom and dad were there then they would be smiling. That stuff kills me."

This is the essence of Brooks' appeal, a unique combination of showmanship and sentiment. Brooks himself is not only aware of this, he dreamed it all up. "Every night must be an event, we owe that to the people," he says, quoting from his own tour programme like a businessman reciting company policy. "That was the theory ling before these stadium gigs ever came along. When it was a club, there had to be something that happened that night so you would remember it. If it meant pushing a piano off into the audience or running down the bar kicking bottles – whatever it took, you found it. That's what we do. We do events. But you gotta weigh the spectacle against the music. I tell the guys who make the place blow up and fly; you do your job and I'll do mine. My job is music, sincerity and honestly. I'll take care of that part."

Such sentiments are not to everyone's taste, of course. Personally, the only things that got me through the Brooks show were copious amounts of alcohol and the thought that I was going to get a chance to take it all out on him the next day. I felt sure that if I could just get him into a room without his entourage I could make him break down and confess to being a devil-worshipping heavy metal fan with a penchant for humping farmyard beasts.

Instead, I got a lesson in what it takes to be a superstar. Always focused, with a quick wit and an astonishing memory (working a room full of journalists and record company people backstage at Croke Park, he picked up everyone's name and never needed to be reminded), you cannot put one past Brooks.

"What do I make of the cynics?" he says, eyeing me up in the certain knowledge that he is talking to one. "All that slicin' and dicin' is part of the gig. I don't let it get to me. I keep something I call 'The Rut'. It's a huge headline that says 'Garth Is In The Same Old Rut' and it's a review of an album called No Fences. Well that album went on to do 14 million for us in the States. It's the largest-selling country album of all time." And then he just leaves it at that, polite enough not to twist the knife that he has just slid deftly between my reporter's ribs.
Brooks does not shy away from direct questioning. He may not be about to confess to being cruel to animals, but, perhaps taking into account the fact that his chosen genre of music has always dwelled on life's hardships, he candidly admits that his 11-year marriage to his college sweetheart Sandy has had as many ups and downs as the average country song. "There's been tough times, tough times," he says, with an unflinching gaze. "Still have them, even to this day. There's times when there's been no communication. Lots of wondering what was going on when we were apart. I was the one that was probably doing 99 per cent of the wrong things but it's like all marriages, you have times when you look at each other and think that sometimes it'd be better to start over…" The thought appears to make him shudder. "Which, God forbid," he adds, with feeling.

Such is Brooks unerringly populist touch, Bill Clinton (himself a fan) must be eternally grateful that the card-carrying Republican chose the music business and not politics. Like Clinton, he comes across as a peculiar combination of gee-whizz country boy and city slicker. He may call everybody "sir" and "ma'am" and extol the joys of a quiet domestic life with his long suffering wife and two yound daughters, but he certainly keeps a close eye on the bottom line.

Records are discussed in terms of "pieces of product" and "units" shifted. He talks about "different formats" and "new markets" with the enthusiasm of a middle manager. Tellingly, the new album is not so much being recorded as "under construction". Brooks is involved in every aspect of his career, from songwriting, to stage design to memorabilia.

"Everything that has my name on it, I'm responsible for," he declares. "This is my one shot; so as far as business is concerned I think I need to be in on those decisions that affect my life and career. So I'll take the blame if it goes wrong, but I sure as hell wanna be in there and know what I'm taking the blame for."
Brooks may be a marketing man's dream – but in this case, as luck would have it, he himself is the marketing man. Unusually for a country singer, Brooks has a degree in advertising from Oklahoma Stage College. And he had applied the skills he learned there to his musical career, citing that the rules of copywriting work equally well for songwriting: "Get to the point, don't waste a line and try and make it something they'll remember."
Although he has had a hand in an enormous amount of hit singles, he always takes the last credit on all his compositions, confessing that his job is not so much to write as to guide other songwriters. "My contribution is probably just what's real for me, what is my point of view, and then they make it into a lyric that is rhythmic and also memorable."

Humble to a fault, Brooks makes no great claims for his musical abilities. "I'm not a big fan of myself, I'm a fan of real writers. I wouldn't say really I'm that much of an artist, because I'm not much of a fan of Garth's voice and I'm sure not a fan of how he plays guitar, but I sure like the fun that goes with the event."

Like many big stars, Brooks has the disconcerting habit of talking about himself in the plural or the third person. "Garth Brooks is a lot more than one person," he insists. "I don't think I could have got sales like we had gotten in the last ten years on my own." The conversation takes on a surreal air as he elaborates on the differences between his public and private selves.

"Garth the guy is a father to three children, a husband to a wife, a guy that tries to keep a farm in balance back home and loves his mum and dad and just kind of hangs out. He's very much of a slob. Very much of a regular guy. I can go out of the house as me, but if someone says 'Hey look, thereás Garth Brooks' then you become that guy, the guy you saw onstage last night. He's one of those big circle G logos. He's the whole thing, the Stetson and the ridiculously tight jeans."

Coming from anyone else, such talk would probably be taken as an indication of an advanced stage of schizophrenia. Brooks' attitude to his public persona, however, seems oddly generous. A self-made phenomenon, he appears less concerned with disassociating himself from his public image as including others in his success. He talks about his musicians as if they are all members of a band named Garth Brooks. He discusses his managers, record company and various employees as if they are all shareholders in an enterprise called Garth Brooks. "This whole thing is very much Garth Brooks," he says, indicating the hive of activity going on around him. "So when you step out, you represent those people. " His employees repay this loyalty with a zealousness unusual in the music business. "Garth works harder than anyone I have ever met," says one of his management representatives. "So you don't mind working hard for him." Backstage, there are none of the drug-snorting, groupie-groping antics associated with big rock shows. Instead you find sober suits, lots of white toothed smiles, and more "have a nice day"s than you'd hear at a McDonalds. It is like a cross between a corporation and a religious cult. One day, I feel certain, there will be a place called Garthland, a huge country and western amusement park for the whole family, where you can go and eat Garthburgers, drive around in Garthcarts, ride the Brooks bucking bronco and pay homage to a huge inflatable blow-up of the king of country.

If so, Ireland would be the ideal place for it. Hanging around the gates of Croke Park was a small army of Garth lookalikes, middle-aged men in bright coloured shirts, spray-on jeans, ten gallon hats and matching bottle-blonde wives. Country music, with its roots in the Celtic lyrical tradition, its farming community values and its peasant tales of hard-working lives, has always been popular in Ireland. But Brooks seems to have taken it to another level, utterly exlipsing home grown Country 'n' Irish talents such as Daniel O'Donnell. "It's become a circle," says Brooks. "The music went west and then it came back."

The grande finale to his most recent album Fresh Horses (released in 1995), is a track called 'Ireland'. "My mom's grandma's family is from Cork, so my mom feels very proud to claim that she is Irish," says Brooks. "Mom believes there are two kinds of people on the earth, Irish people and those that wanna be Irish. But the last thing I want people to think is 'Oh great, now Garth thinks he's Irish'. The song is just a heartfelt thank you for what happened here."

What happened here, of course, was The Point. Although a superstar at home in the USE, Brooks does not mean a great deal outside of dedicated country circles elsewhere in the world. So he was astonished when during his 1994 world tour, he sold out eight shows at The Point in Dublin, performing in front of 64,000 people who apparently knew all of the words to all of his songs.

"This whole thing is built on confidence," he says. "And there are levels you go to that only confidence can get you past and on to the next level. The gigs we did at The Point gave me the confidence that our music could stretch across the water, and that somebody, other than in my own back yard, got what we were trying to say."

Using Ireland as an international beachhead, Brooks' ambition is to prove that "country music can deliver as many units worldwide as rock and rap and pop." And if anybody can do it, Brooks can. He is a man who appears to have everything under control, bar his emotions. But the tears are his secret weapon.

"You gotta bleed when you're making records," he declares. "Once you have done that, and it becomes that disc, then it's a piece of product and you move it like that. But people can hear whether your heart and soul's on that or you're just going through the motions."