One Direction have admitted being so successful is tough - because it keeps them away from their families.
The five lads said that watching back their film, This Is Us, was hard because interviews with their nearest and dearest made them realise what they were missing out on at home.
Liam Payne, whose father is shown in the film talking about "losing" his son, said: "He's always so happy when I see him and happy to have me home. To actually see what he's like when I'm not there is a bit mad."
The band's families are all seen talking about what it was like to send their children off to an audition for The X Factor when they were just 16 and to have barely seen them since.
Louis Tomlinson explained that most parents would expect to see their children fly the nest at 18 to go to university, but for the One Direction families it had been different.
He said: "For us, it happened out of the blue. Our mums had to wave goodbye to us on The X Factor. It was a lot for them to take in at first."
:: One Direction: This Is Us is released on Thursday, August 29