The 'Kiss You' hitmakers - consisting of Niall Horan, Zayn Malik, Liam Payne, Harry Styles and Louis Tomlinson - decided to celebrate their success with a trip to Las Vegas, the gambling capital of the United States, but received a "dressing down" when they lost a significant amount of money during their raucous night out.
Niall explained to We Love Pop magazine: "Like most of the stupid things we do, it seemed like it was a good idea at the time. We just thought, 'We're 18, this is the first time we've been able to spend a bit of money in weeks because we've been on the road.' I won £100, which seemed reasonable, then I stopped. But I'll have to say 'no comment' about the others.
"Let's just say it got a bit ugly and a lot of money was lost. A lot. When our management found out, we got a serious dressing down about it."
Although the young band may have their wild moments, they keep each other grounded.
Louis said: "I think that's the beauty of being in a band. Often people who have had fame from such a young age as solo artists find it harder to stay grounded, because it's just them. But with us, we've got each other. The minute one of us falls out of line, another one of us will set them straight!"