One Direction star Niall Horan believes the band's Beatlemania-style success is down to perfect timing -- and hard work.
The band sparked hysterical scenes across the US after performing songs from their second album on the country's top talk shows.
The Irish teen said they exploded on to the charts at a perfect time, as there was a lack of boybands.
He said: "With America, it was a mix of hard work and luck, as there was a gap in the market. When you get over there you either go hard or you don't go at all.
"We spent ages touring and doing promotion over there, working solidly."
In an interview with 'Cosmopolitan', the handsome teen also revealed how he has fallen in love once before but he declined to identify the mystery girl.
The 19-year-old said he couldn't resist a girl who could play the guitar.
"I'm not really a flirt. I've got loads of good female friends, like Tulisa, but every time I'm pictured with her, people say we are going out."
The blond singer, who is said to be the most popular of the group in America, also said he counts his smooch with Katy Perry as his best-ever kiss.