When McFly and two of the three members of Busted decided to formally join forces last year to form McBusted, the excitement was palpable.
And now the boys are on the verge of headlining a day of festivities at Hyde Park on July 6 which also includes 90s heartthrobs the Backstreet Boys, The Vamps and Scouting for Girls.
Last year, that high profile slot belonged to The Rolling Stones.
McBusted and McFly bassist Dougie Poynter, 26, told News Shopper: “It is going to be one of the biggest we have ever done. We’re all super, super excited about it. We can’t wait.
Dougie won I'm a Celebrity Get Me Out of Here in 2011
“The whole thing is super-overwhelming. There have been some amazing people that have played there. It really is going to be one of those gigs we never forget.
“I think we are going to try to have double the fireworks (The Rolling Stones) had.”
McFly - who formed in 2003, have had seven number ones and sold seven million records worldwide – and Busted – four number ones, four million albums sold – may have only decided to link up last year but the two groups have plenty of history.
Throughout their careers, they have written songs for each other. Tom Fletcher even auditioned to join Matt Willis and James Bourne in Busted before going on to help found McFly.
The younger band’s first major gigs were supporting Busted.
Dougie, who joined McFly aged 15, said: “It didn’t feel weird at all.
“If anything, it was exciting. The energy has gone through the roof, it’s great.
“Our bands have always been best of friends and written each other’s songs anyway so it’s more weird to the public who maybe didn’t know that than it is to us.
“James used to live with us, we were on the same management, they helped launch us – it really wasn’t that strange at all. It was just like adding two extra best friends to the group.”
Though McFly never went away, the two remaining members of Busted (Charlie quit in 2004) spent a while in the wilderness working on other projects, and Dougie admits it is great to see them back on stage.
He said: “What’s great is they seem to have a lot of pent up energy. Matt and James go absolutely nuts on stage like they have been locked away for a few years.”
As a supergroup, they pull out all the stops in their live show, too.
Dougie, who won I’m a Celebrity Get Me Out of Here in 2011, said: "We definitely aim to entertain.
“Nobody really likes to stand around not doing anything for too long, so we come off stage absolutely drenched.
“We don’t take ourselves too seriously, so there’s a whole bunch of schtick throughout the show and gags.
“On our arena tour we had giant inflatable boobs and James and Matt arrived via Delorean to the stage.”
He added: “We have been working on what we can take from our arena show and make it bigger and more of an outdoors thing.
“We have looked into everything. Literally everything. At one point someone was looking into if we could have the Red Arrows flying over. We love spending tonnes of money on shows.”
McBusted are currently supporting the phenomenon that is One Direction – with whom they have been writing - on a stadium tour of Europe, and working on winning over the Directioners.
Dougie said: “They have been awesome.
“We like playing any show, really – big or small or not even to our crowd.
“If anything, playing to a crowd that is not your own is way more challenging because you have to give it 10 per cent more and you think about it a bit more. It is a bit more of a challenge.
“They seem to be digging it by the end of the set.”
The six are obviously enjoying playing together and Dougie said they hope to continue.
He said: “We are definitely going to do this for a while. Everyone is super, super happy so we have no reason to stop and do separate bands again.
“We’re going to do this for as long as it’s fun.”
McBusted will headline at Barclaycard Presents British Summer Time Hyde Park on July 6, Weston-super-Mare Beach on Saturday, June 28 and Ipswich Chantry Park on Sunday, June 29.
Go to bst-hydepark.co.uk for tickets and info about the London gig.