Boyband Five on their reunion: We are spectacularly lucky to get a second chance

There weren't many boybands bigger than Five in the late 1990s.

But at the height of their popularity they dramatically called it a day in 2001, as the stress and pressures of fame and an unrelenting schedule took a toll on all of them.

Now, decades later - and to the delight of Millennials - Scott, Ritchie, J, Sean and Abz are back.

"It was too much too fast. Way too fast," Abz tells me, while Ritchie explains it was "like being strapped to a rocket".

"I think I was just in survival mode for five years, because I can't remember a thing," Sean adds, who was just 15 when the band was formed.

They have invited me into the rehearsal studio ahead of their upcoming tour, 25 years after they were last on the road together.

And it's clear they're much more comfortable this time around, with J saying they feel "spectacularly fortunate" to have a second chance.

The group sold more than 20 million records in the late 1990s and early 2000s, with tracks such as Keep on Movin' and Everybody Get Up.

But reuniting after more than 20 years doesn't come without risk. Oasis may have sold out a stadium tour in seconds, but others haven't been as fortunate.

Scott says all five of them didn't sleep the night before their reunion was announced.

"I phoned my wife, Kerry, in the middle of the night and asked: 'What if no one cares? What if we think it's going to be this big thing and everyone goes, so what?'"

But fortunately, the group's fans did care, and the band's arena tour of the UK, Ireland, Australia and New Zealand is almost sold out.

"We knew we'd done well but I don't think we realised how well our younger selves had done. And how much we'd affected some peoples lives and how much they'd loved us," Ritchie says.

Another thing the band were unsure about was the prospect of singing and dancing together again.

Sean explains: "We sold a tour without even knowing [we could do it]. We believed it but we had to get into rehearsals to actually find out, but we can confirm it's still there!"

The band are now all in their 40s but had barely left school when they formed. It was clearly an overwhelming time.

Ritchie tells me: "We got into it very young and we thought we'd won the lottery and all our dreams were coming true. In many ways, they did, but in some ways it turned into a nightmare psychologically, [there were] a lot of things we weren't expecting.

"We'd wake up on a tour bus and think, not what country are we in, but what continent are we in?"

J agrees: "There are loads of blank spots in our memories, and we've spoken about it and come to the conclusion that it was all so fast, and we were in flight or fight mode for the whole thing. It was like you were being chased by something."

So after all that time apart, I want to know who made the first move about the prospect of reuniting.

Scott says that not even being in the same room with his four former bandmates for over 20 years had been playing on his mind.

"I phoned Abz and I hadn't spoken to him for 10 years, and one of the first things he said to me was 'It's so nice to hear your voice'. So we just got together - it wasn't about a tour, it was about being friends again.

"No one outside this bubble knows what we went through," he adds.

Though one person who knows more than most about what Five experienced is Robbie Williams, who was a member of Take That before finding success as a solo artist.

Five performed Keep On Movin' with him at one of his shows in London this summer.

Ritchie says he had "performer insecurity" and feared the crowd wouldn't know who they were, "but it went off".

Sean adds that Robbie "knew everything we've been through", adding the six of them sat for two hours chatting.

On the emotional trauma Five went through, Scott says Robbie told them it was like "carrying a big bag of rocks and you need to empty it day by day."

For J, the whole experience of being back in the band is "the antithesis of what it was before."

"The people we've got around us, how we're being managed. how we're being looked after, which is the most important thing. We were last time but people were kind of learning on the job."

They've reconciled and reunited now but would Five go back in time and do it all again?

Abz says he would "but differently", while Ritchie laughs: "With this head, I'd love to do it, because I'd be checking the accounts a lot more!"

Five: Still Movin' is on the BBC iPlayer from Tuesday 28 October. Five begin their tour on Wednesday 29 October in Cardiff.