One Direction claim their success is down to the fact they are still the same ''immature'' boys they were before they became famous.
One Direction insist fame hasn't changed them.
The 'Live While We're Young' hitmakers claim they are so successful because they are just normal guys and are truly the best of friends.
Newly single Liam Payne, 19, said: ''For us, the main thing is we've just been ourselves. Lots of people get into our situation and you hear that they've changed. We've just stayed as ourselves.
''There's a lot of things the fans don't know about us. People still ask whether we really get on or not - and we genuinely do. A lot of people don't believe that.''
The boys - who were put together on Simon Cowell's talent show 'The X Factor' UK in 2010 - think they have broken the mould of what boy bands are supposed to be like by acting their age and not being afraid to look ''stupid''.
Louis Tomlinson, 20, added in an interview with Wonderland magazine ''I think previous boy bands felt they had to meet a stereotype. We're just ourselves - stupid, immature and quirky.''
One Direction - also comprised of Zayn Malik, 19, Harry Styles, 18, and 19-year-old Niall Horan - are being forced to embark on a gruelling fitness regime ahead of their eight-month run of shows kicking off in December.