After four albums and 10 million record sales, the five Irish lads decided to split in 2000 - cue sobbing fans all over the world.
But in 2007 Ronan, Mikey, Stephen, Keith and Shane decided to go through it all again when they reformed, and you can see the band back in action at Sandown Park Racecourse next Thursday, August 6.
"I'm into the horses myself – I've got two of them," says Mikey Graham. "Ronan is well into horses too. It's just a great day out, it really is good fun. Everyone brings their families along and they have a flutter on the horses, and then there's the evening's entertainment. Who knows, we might get a couple of tips and win something."
The boys were international stars as Boyzone, travelling around the world and enjoying huge success with number one hits such as Words, A Different Beat and No Matter What, but Mikey says in some ways it's better coming back after the reunion.
"It's just a great experience this time round – I don't know if it's because we're older or what, but we're taking it all in, absorbing more and savouring it.
"The industry has changed a huge amount compared to 15 years ago. We would have to travel to every local TV and radio station or come into the record company to do interviews, but now because of Skype, the internet and mobile phones we have a lot more time."
And of course the band now have families to take into account, something that wasn't a concern first time round.
"Last year, fitting the tour around my family was my concern. But my wife and two daughters are on tour all the time with me. It really works fantastically well bringing the kids along. My family enjoy it and it's really turned into a family affair. It works out much better because we're not away and missing our families like when we were young lads.
"Hannah (my daughter) is 13 and she's absolutely loving it – she gets all dressed up for coming to the concerts. She loves the idea she has access all areas and can go backstage. It's a weird thing looking at her dad on stage and all these fans screaming at the top of their lungs, but I've made her very aware that it's just my job. On stage I've got the Mikey persona, but when I come off stage I'm just dad and that's it."
Despite the positives to coming back and the support from his family, Mikey had fans worried last year when he had to drop out of some dates due to exhaustion.
"It was a weird time in November. I don't know what happened to me. I was having panic attacks and all kinds of things. I used to have similar problems when we first started out because I was plucked from obscurity and thrown into the limelight. In the years apart things had settled down a lot and I think I had a bit of difficulty changing my life again."
Luckily, he confirms he's feeling fine again now and is looking forward to the upcoming gig.
So what made the five Irish pop stars want to go back to a life of gruelling tour schedules?
"My wife is a good friend of Gary Barlow's wife and I got to know them well through the years apart from Boyzone. I didn't miss being apart from the band but when I saw Take That's show I thought, 'I could do with a bit of this again'. I put in some calls to the other lads. Quite a few groups from the nineties have tried it but only some have been successful. I was nervous about it because if it fell on its backside, whatever reputation we still had as being one of the top pop bands of the nineties could have been destroyed. All people would have remembered would be the reunion flop. Thank God everything is ok.
"The original fans bring their children and husbands, and we've got new fans, too. At a Boyzone concert the fans range from nine to 90 years old.
"The things we wanted out of the band this time had changed because we had all changed, all grown up and are men compared to the boys we were then. We run the Boyzone machine now, and although Louis Walsh is still involved, we call the shots."
Boyzone have always encouraged other Irish pop acts and on their current tour they've welcomed X Factor star Eoghan Quigg as a support act.
"Eoghan's having a great time – he's a great kid and he's too cool for school really. He's very, very calm for a kid of his age."
The band have a single out before Christmas and are releasing a new album in spring next year, which could feature a few unexpected collaborations.
"With the album, all avenues are open and all possibilities are available. We've looked at working with Leona Lewis, Mark Ronson and Jay Sean but that's not to say any of it will be the final result."
In the seven years apart from the band, the five Boyzone lads all pursued different projects – Ronan had a successful solo career, Stephen went into the West End, Keith took up acting and a part in Coronation Street and Shane starred in programmes such as The Games and Celebrity Love Island.
Mikey's tried his hand at a solo album, producing and acting and says he's going to keep up with the other strings to his bow even now Boyzone are back on track.
"I was steamrolled into doing a solo project and in hindsight I should have taken a break away from it all. The music was far too different from Boyzone and it was a bit self-indulgent, trying to prove to myself and other people I was a serious musician. It was never going to work – the album is a nice album but I've no aspirations to do it again.
"I love being with the band and my main gig is songwriting and music production. I went back to college to do music technology and sound production after Boyzone.
"I also went to America and trained with Brad Pitt's acting coach, and made some movies.
"I'd like to concentrate on writing and acting if I have the time. I love it, I love being busy.
"I love to be able to do the Boyzone thing and take a break here and there. I really appreciate it far more now than I did before. Years ago we worked so hard, but almost reluctantly because we were young and wanted to have a good time. We work as hard as before but now we can take breaks if we need to.
"We definitely appreciate it more, 100 per cent."
Katie Archer
Boyzone are at Sandown Park Racecourse on Thursday, August 6. The concert is at 8.40pm following an evening of racing. Tickets for racing and concert from £25 (children and group tickets available) – go to www.sandown.co.uk or call 01372 464348.