"Liam Payne, who dates dancer Danielle Peazer, told Daily Mirror: 'Our tour manager told us it would take three years of hard graft to do well in America.. so for it to have taken off as it has is incredible.. Twitter has been a major factor in getting our name in the States. Just as Twitter has gone up, so we have, too. They've gone hand in hand. And, picture-wise, Tumblr has helped us a lot. It has really accelerated our success.'

Niall Horan’s father Bobby is worried about a potential comedown for the boys: 'The only thing I'm worried about is hopefully it'll be a long period being at the top. The comedown from that, I'm a little bit worried about. It's always at the back of my mind. You're up there on a high, but it's a big drop after that.. But he seems to be coping with everything brilliantly, a lot better than I would.

Niall told me on Tuesday night that they were going to get to number one. It was a surprise to him, and it was to us as well. We thought they were going to be close but they didn't think they'd make number one. Thank God they did. They've been there for the past couple of weeks doing promotional work and they have worked their butt off. He's very grounded but he's buzzing. He's on a real high now."