Irish pop group Westlife have announced the departure of member Bryan McFadden at a press conference in Dublin.
The group said the split was amicable
A spokesman for the group read out a statement that said: "In the tradition of all great groups - Westlife are now a four piece."
McFadden said he was leaving to spend time with his family, and his split had nothing to do with the other members.
"It's to do with me. It's hard to juggle two lives when you've got a family," McFadden said.
"I want to concentrate on my family and being at home as much as I can," he said.
McFadden, whose wife Kerry won ITV's recent game show I'm a Celebrity... Get Me out of Here, said the other members of Westlife were "my four best friends in the world".
'We love you'
The group said they were "devastated" by his departure and called on the group's fans to continue supporting them.
Westlife singer Kian Egan read out a letter to McFadden in front of reporters.
WESTLIFE'S NUMBER ONES
Swear it Again
If I Let You Go
Flying Without Wings
I Have a Dream/Seasons in the Sun
Against All Odds
Queen of My Heart
World of Our Own
"We have shared our dreams. We understand and respect your decision. From the bottom of our hearts we love you," he said.
The four remaining members - Egan, Shane Filan, Nicky Byrne and Mark Feehily - said they looked forward to seeing McFadden at one of their forthcoming Belfast concerts.
They are also working on their new album, a collection of duets with contemporary artists.
Westlife notched up 12 number one hits after first topping the chart in 1999 with Swear It Again.
Their latest single - Obvious - is currently at number 10 after entering the chart at three.
The McFaddens have been tipped as a TV presenting duo
The group broke records by becoming the first group to achieve number ones with their first seven releases.
When they first emerged they were marketed as the new Boyzone - five good-looking single Irishmen - with Ronan Keating originally billed as their co-manager.
Bryan McFadden has co-written the Irish entry for this year's Eurovision Song Contest, which will be performed by Chris Doran.
The group insisted Westlife would continue.
"At this moment we just hope the fans stay with us, we need them now more than ever," said Nicky.
"We need their support and so does Bryan."
Gennaro Castaldo, of music retailer HMV, said the Westlife were " talented and big enough" to overcome the loss of a member.
"They have a devoted following who will continue to buy their recordings and go and see them in concert," he said..
"However, just like Robbie leaving Take That and Geri breaking from the Spice Girls marked the beginning of the end for their bands, Bryan's departure must surely signal a similar fate for Westlife."
BBC News Online users sent in their opinions on McFadden's departure and Westlife's future.
Oh I'm so heartbroken. Are they going to set up a helpline???
Jo, Walton on Thames, Surrey
I urge all fans of Westlife to continue supporting the band. If Westlife were to split there is no one fit enough to take their place.
Nicola, Glenrothes, Fife
Oh my god. I really hope that Bryan's departure won't lead to the break up of Westlife. They have got years left in them yet. I will continue to support them but Bryan it just won't be the same without you. We love you!
I'm gutted. Bryan's always been my fave despite the fact that every one of the lads has a special kind of something. I've got to know them pretty well through these five years because I run their Spanish official fan club. I can speak for a lot of fans when I say that none of us expected this so soon. Personally, I always knew Bryan would be the first to step out the band. Despite that, I know the lads share a fab friendship and it'll remain stronger than ever now. They can count on my support now and forever. Thanks for the good laughs Bryan.
Alice, Barcelona, Spain
The concerts will be just as good, only different to the last few years so let's support the other four and look forward to more good music.
Tania, Crewkerne, Somerset
The only sad thing to come out of this is that the rest of the band decided to carry on instead of calling it a day and giving us all a break.
Trev, Hinckley UK
Your family always comes first and Bryan has chosen this path and that enough is enough, but Westlife will survive this loss. They will make a perfect foursome.
Kathryn Barker, Warrington
More to the point, do we care?
Thank God for that! Let's hope the rest of the manufactured members of Westlife follow suit very quickly and we lose them into the bargain bin with all the other nasty talentless boy bands!
Bryan, Westlife will not be the same with out you.
James Lynes, Looe, Cornwall
Westlife are finally crumbling! Woohoo!!
David Sztypuljak, London, England
I feel sick to think of Westlife with out Bryan. I love him. He is the fittest member of the band and I will not listen to Westlife till he comes back. I love him. Kerry can manage for a while without you, I can't. I love you.
Sophia Cockerill, Chislehurst, Kent
Can I have a refund on my 2004 calendar and 1/5 off the price of my tickets? I'm gutted.
Stephen Payne, Devestationville
Another nail in the coffin for manufactured pop. It won't be long before the rest of the lads split now. They may have had 12 number one singles but they're not even in the top 50 all time singles sales list. That tells you something about the state of the British singles charts!
Kieran Stock, Chelmsford
Oh I'm devastated, our Bryan was the life and soul of the band, I won't be sleeping normal tonight. I have one question... Why Bryan?? WHYYYYY??
Micky O'Donohue, Middlesbrough
Only four more to go!
Paul Hart, Worcester, UK
It's just pathetic, Westlife will never be the same again, he should have at least for the world tour which I have bought a ticket to go an see. It's not good enough, I'm heartbroken,
Crystalle Smith, Leicester, England.
I have a new goldfish, its name is Ben, now that's more interesting news surely...
I suppose it would be too much to hope that the remaining four members cancel plans for their next album and split the group entirely?
Simon Murphy, Amsterdam, Netherlands
I'm upset, but families should come first. It's a shame he couldn't stay for the world tour, I'm still excited about it though!
Sarah Ife, Leicester, England
To be honest I'm glad he's leaving the group (notice I said group, not band).I don't like Westlife but he always seemed the most intelligent. From one Irishman to another... good on ya!
Ben Mulligan, Ireland
I'm 28 and a mother of two and we all love Westlife. I've seen them in concert four times and am due to go again in May. The news is devastating but understandable - I wish Bryan the best of luck and am glad to see him so happy. I certainly will continue to support them they are extremely talented but Bryan will be missed. Good luck to them all .
Helen, Leigh, Lancashire
I'm devastated. With that useless lump leaving I thought they'd split for sure.
Gavster, Paisley, UK
Of course Westlife can survive with Bryan, although he is quite a character I don't think he was the backbone of Westlife. I must say it's a nice change to see a member of a band leaving on good terms which just goes to show what good friends they all are.
Tuarita Lawson, Bristol, UK
I haven't been able to think of anything else today! I wish Bryan good luck and also the four remaining members, but he will be missed as he such a character! With love, Anna
Anna Werinius, Lerum, Sweden
Good news! Let's kick out all the teeny pop bands!
It will be a shame to see him go, however, I believe that he will now become a true star in his own rights - this man has a lot to offer to the entertainment world - I wish him all the luck in the world!
Rose Tabersham, Esses, England
Please Bryan... don't go! We love you. I do feel that Westlife will be able to carry on. I just hope that we will still see Bryan at concerts! Please Bryan come to Telewest Arena, Newcastle!
Nathalie Burgess, County Durham , England
So what, I'm sure there is another throw-away manufactured band waiting to take their place.
I believe he has made the right decision for his families' sake, but he could have waited till after the tour as lots of the nights are sold out so he could of waited and brought it up whilst on stage in front of fans than media.
Laura Dunn, Amble, United Kingdom
I can't believe this has made the BBC News web page! With so many other topics in the world today, I cannot even bring myself to find this refreshing. A band that has had 12 number ones, with half being covers of much better artists - I say it's no great loss, to the band or the music industry.
M Jones, London
They all look and sound the same (ie bland and ordinary) so who will be able to tell the difference? Good luck to him - quit at the top.
I think it's SO SAD! I hope they'll continue and be successful. But I think it'll be a big shock for all of the fans!
Diana Kristjansdottir, Selfoss, Iceland
No great loss, as together with Kian and Nicky, did very little solo singing on the group's tracks and these blonde himbos are the Shane Lynch, Mikey Graham and Keith Duffy equivalents from a previously flawed boy band where only two others could obviously sing.
Mark O Sullivan, St Helier, Jersey
Westlife were probably reaching the end of their shelf life anyway - with some of them now married and with children, and at least one other one engaged, the Irish boy band became a man band long ago, just like Boyzone did.
Catrin, Aberystwyth, Wales
I think he should wait until the end of the tour before going as it is a shame for the fans - myself, two daughters and niece included who have bought tickets to see them as a five piece. Bryan is my youngest daughter's favourite member and now she won't be able to see him for a last time in concert.
Sandra, Kinloss, Scotland
I think Bryan is selfish and a very sad man. If his wife Kerry never won I'm a Celebrity..., Bryan would still be in Westlife.
Martin Duckhouse, Walsall, West Midlands
It's bang out of order - he isn't even doing the tour! I am going on 16 April in Glasgow SECC - it won't be funny cause Bryan is the funniest. I knew he would b the first to go but I thought he would have done one more album before anyone left.
Cheryl Anderson, Edinburgh, Scotland
Here's 20p... call someone who cares.
Maya McKee, Southampton, UK
I'm devastated. I feel as though my heart has been torn out. The fabric of the cultural life of this once great nation has been irrevocably torn. Will life ever be the same again? I'm sorry, I can't go on. My tears are making the keyboard slippery...
Who the hell is bothered apart from young pop-obsessed school girls? Will Westlife continue to have success without him? For the sake of music let's hope not.
Mike, Sussex, UK
Of course they will continue to have success, they are very talented (not to mention gorgeous) lads and they will top the charts even without Bryan!
Louise cook, Crawley, England
Westlife will continue to go strong because they are a successful boy band since Take That in the 90's. Bryan is now going to spend time with his wife and his two little girls. And this could be Bryan's chance sometime in the future to make some solo success by being a solo artist.
Ann Marie Lynch, Liverpool, England
If Bryan McFadden's departure leads to the break-up of Westlife then hoorah for that. Music these days either seems to be rappers sampling other peoples' work or boy/girl bands performing lame overproduced cover versions that never hold a candle to the original.
Philip Branigan, Blackheath, England
Westlife won't even notice that he's gone. It's not like he had anything to do with writing and producing their "music"...
Didier Blanchard, Manchester
I just hope he has not left with some misguided intention of having a solo career as the words "not a chance" would come to mind... he did well in Westlife due to the talents of the rest. Well, I say talents...
Peter Taylor, Sunderland, Tyne and Wear
I hope it is the end now! Westlife really are past their sell by date. Now it's time for Phixx to fill the void.
Everyone has so many bad things to say about Westlife - they are quick to forget the fans for whom the band have brought so much happiness. It's easy to forget with everyone's obsession with credibility in the music world that the members of Westlife are people too.
Rosi Crawley, Bath
Since I was about six years old Westlife have been my favourite boy band ever. They've given me inspiration and answers to life, each and every one them. The news about Bryan leaving the band is very painful because Westlife can't stay the same without a missing member, no matter who the member is.
Maya, Lebanon, Beirut