Harry Styles, Louis Tomlinson, Zayn Malik, Niall Horan and Liam Payne all arrived on the red carpet to the sound of their hit song 'What Makes You Beautiful', as the Morgan Spurlock-directed documentary received its first official screening.
The lads - all looking dapper in black outfits - caused hysteria as they greeted fans and posed for endless photographs outside the central London cinema.
They were supported by a whole host of their showbiz chums, including boss Simon Cowell, who was back in Britain after his recent baby scandal.
Many fans were warned to stay away from the premiere and watch it from home and, by early afternoon on Tuesday, Transport For London were warning fans that the area was full to capacity.
'This Is Us' follows the boys' life on the road during their 'Take Me Home' world tour.
Harry said the film would allow fans to learn more about them as a band, telling 'BBC Breakfast': "We just want to show what we're about and with social media and stuff there's only so much you can get across in terms of your personality."
The band also held a press conference on Monday where Liam admitted there could be a follow-up to the film if the first one proves successful.