One Direction are currently in the US for their sell-out headline tour.
Singer Liam Payne has admitted that the fans are even trying to get pictures of them in the gym.
Payne told the Daily Star: "It's gone a bit mental. We were in the gym after we checked into the hotel and people were trying to film Harry.
"Loads of fans have been in the hotel lobby - and some of them even check in. I don't know how they can afford it."
Liam, Harry Styles, Louis Tomlinson, Niall Horan and Zayn Malik have sold over two million copies of their single What Makes You Beautiful in the States.
The boyband is to release a DVD of their debt tour on May 28, and will play the iTunes festival this September.
Liam said: "The DVD is a chance for everyone who couldn't get tickets to see our show, as well as it being a memento for those who did come.
"Our shows have got progressively better ever since, as have our voices. It's been nice to see everyone improving."
However, despite all the success Liam admits he still worries about remembering the lyrics.
He admitted: "I'm really nervous I'll forget my words but the fans are always there to help."
This article is powered by Well Contented Ltd