Girls Aloud, JLS and Oasis. What do they all have in common?

Nostalgia.

It’s everywhere, from music and movies to games and TV shows – and it can be big business.

When the Gallagher brothers announced their reunion tour earlier this year they were the latest household name to spark a ticket-buying frenzy.

Now Busted and McFly have announced a “mega tour” – co-headlining a series of dates around the UK.

Both bands have been around since the early noughties and have had their fair share of break-ups, reunions, hiatuses and comebacks over the years.

It’s not the first time the two have joined forces.

Back in 2014, members of both formed “supergroup” McBusted without Busted frontman Charlie Simpson.

Now he’s back, and for fans it’s a dream reunion and a chance to relive their memories.

But can you have too much nostalgia?

When BBC Newsbeat speaks to Busted’s Matt Willis and McFly’s Harry Judd ahead of their rehearsals, Matt admits the groups were “quite shy of that word”.

“We didn’t want to be nostalgic,” he says.

“It’s something you never want to be as a band.”

But, Matt admits, the power of nostalgia is “massive” and there’s nothing like the feeling it gives you.

“It’s a huge thing when you feel that,” he says.

“There’s certain things about our bands, which remind people of a pinnacle moment in their life.”

Harry says there are times when both bands want to move on because they’re still releasing new music.

“But also, be proud of your past and let people enjoy that nostalgic feeling,” he says.

It’s an emotion star girl Melissa Larsson, a fan of both bands, is happy to experience.

“I personally live on nostalgia,” she tells Newsbeat.

“We were younger, it’s a nice memory… people look back fondly.”

Melissa agrees that there a lot of comebacks and reunions right now, but is convinced the bands genuinely enjoy working with each other and hanging out.

And she wouldn’t mind if some of her other favourite bands followed Busted and McFly’s lead.

“I don’t see it as a negative whatsoever,” she says.

Nostalgia isn’t a guarantee of success for established bands, but it doesn’t hurt, either.

Kriss Thakrar, from analytics company Midia Research, tells Newsbeat comfort and familiarity are one of the biggest draws for long-time fans.

“Nostalgia really kicked up during the pandemic when people were seeking comfort from the chaos,” he says.

“The world is still a pretty chaotic and uncertain place so the drive toward nostalgia hasn’t subsided.”

He also tells us that is more difficult to break into music now, resulting in less new music and fewer artists able to make an impact on culture.

“Following niche artists may not work for everyone and in some ways nostalgia feeds into a longing for a more mainstream past that has been lost”.

The bands had been building up to the joint tour announcement over the summer, framing the gigs as a battle of “Busted Vs McFly”.

After sharing 21 years in the spotlight, the boys say the hook for the upcoming shows is them settling once and for all the “underlying rivalry” between them.

When two beloved groups announce a comeback it usually generates headlines, but do they ever worry that they’re holding newer bands back?

“I don’t think so, no,” says Harry.

“We always look forward to having support acts at our shows and supporting young artists.

“This year, I’ve had a band in the studio and recorded four tracks for them.

“Hopefully we’re not getting in the way of anyone’s potential success.”

It’s easy to write off reunions as a lazy cash-in, but the dedicated fans who are likely to turn up will want an experience to remember.

Obviously, Harry and Matt say they want to give everyone at their concert the best night of their lives.

And, Matt says, while it’s up to bands to choose what they offer in terms of premium tickets, there’s a limit to what people will put up with.

“If you make every ticket extortionately expensive, then it’s so out of order on most of your fan base,” he says.

As for whether they’ll still be playing in the Year 3000, they’re not sure – but they don’t see themselves stopping yet.

“What are we going to do, retire because we’re successful?” Matt says.

“Can I see myself doing this at 50? I don’t know,” he says. “Right now, I love it, and I’m fully invested.”

Harry adds: “Nothing compares to being on a stage with your instrument playing to your fans, nothing beats it.”

“I can’t ever see myself not wanting to do it,” he says.

Listen to Newsbeat live at 12:45 and 17:45 weekdays – or listen back here.