Westlife and Louis Walsh were a match made in heaven - but it hasn't always been smooth sailing.
The former X Factor judge first hit the big time when he decided to create an Irish version of Take That by holding open auditions for singers, which resulted in the formation of Boyzone.
After many successful years together and working with Ronan Keating as a solo artist, Louis, who turns 70 today, went back to the boyband formula with new band Westlife.
Founded in Dublin in July 1998, the group originally consisted of Shane Filan, Mark Feehily, Kian Egan, Nicky Byrne and Brian McFadden, who would depart in 2004.
It was Shane's mum who first got in contact with Louis and they started working together, but they failed to secure a record deal with Simon Cowell, who wanted to change three of the members.
The X Factor boss told Louis: "You are going to have to fire at least three of them. They have great voices, but they are the ugliest band I have ever seen in my life."
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Louis would later explain to the Irish Times : "He wanted me to change four of them. He wanted to change Shane."
The cunning music boss went away and dyed Shane's hair and apparently Simon didn't realise. "That's a true story," he said.
When asked if Westlife different to Boyzone, Louis confessed: "They were different in that they knew what they were getting into . . . They were less trouble.
"They were probably less fun. But they knew what they wanted and they had great voices . . . 16 number ones."
Westlife is the act with the most number one debuts on the UK Singles Chart as well as eight number one albums.
They were the biggest selling album group of the 2000s and have sold over 55 million records around the world, but it hasn't always been harmonious.
Back in 2010, the band revealed that in their early days Louis constantly threatened them with the chop and would call them 'fat'.
Kian said: "We lived in fear of Louis. He was like 'You're done. I'm going to kick you out of the band. I'm going to put you on the next plane home. Only four people can fit in a taxi, not five'."
While Nicky added: "Louis was always on at you. The first thing he'd say was, 'Your teeth are fecking terrible'. I remember saying once, 'Your teeth are f***ing horrible too'."
Traumatised Shane said the early days were "f***ing horrendous", and did his impression of Louis' vicious taunts.
He said: "Louis would say 'You look fat. Watch yourself, there are only three Bee Gees."
But despite all the abuse, the Westlife boys forgave Louis for how he trated them at the start.
Shane added: "Oh we're all fond of Louis. Simon's now doing to him what he did to us, so he's gone and got everything done. His hair's browner, and his teeth are whiter."
One of the most shocking moments came before they hit the big time when Shane messed up his audition in front of Simon.
Shane previously spoke of the incident, revealing in 2014: ''We walked in and we met this man called Simon Cowell for the first time. It didn't go well and Louis wasn't very happy with me afterwards. He kind of lost it. He slapped me in the face.
"It was crazy. He was shouting 'what are you doing' and he was shaking me and saying 'I was counting on you in there.'
"I thought my life was over. I thought that's it, I've ruined my life. It was horrible but he said 'don't worry, I've got a plan."
The band revealed Louis was very strict with them and kept them with a 'squeaky clean' image.
"We liked to have a drink but that was about it. We never did drugs, we didn't get involved in any mad, crazy sh** or anything like that," Shane told Digital Spy in 2015.
"I think we were generally clean enough individuals anyway because our mums and dads would've f***ing killed us if we weren't. Louis was always very strict with us to a certain degree. He always reminded us how lucky we were," he mused.
"He'd be always watching everything. He had disciples out listening to us. It was crazy how much he knew about our lives outside work hours, but that's what a good manager does. He kept us together as a band, that's his job."
Louis turned 70 today - and Westlife made a cheeky dig at their boss ahead of their sold out Wembley Stadium concert this weekend.
Speaking on This Morning earlier, the band revealed they had texted their manager wishing him a happy birthday, before Nicky joked: "Is he one? No, no. Is he two? No, no."
Bandmate Kian then hilariously added: "That could go on for a while," before the group collapsed in laughter.
One of them also shouted: "Happy 50th birthday Louis!"
Mark then poignantly said: "I think that when it comes to Louis, the way he plucked us and put us onto the map, this gig, this weekend, Louis is a huge part of our story.
"Between us and him being here, we think back to the band starting in high school. It is very much a milestone event in our career."
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