One Direction's This Is Us, a documentary following the band's rise from X-Factor contestants to one of the biggest pop groups in the world. The documentary premiered in London on Tuesday (20th August) in Leicester Square, London. Screaming fans awaited One Direction and the other celebrity attendees.

One Direction
One Direction from L-R: Harry Styles, Niall Horan, Louis Tomlinson, Zayn Malik and Liam Payne.

The band which consists of Harry Styles, Zayn Malik, Liam Payne, Niall Horan and Louis Tomlinson; all attended the premiere and greeted fans of the red carpet. The band was formed in 2010 on The X-Factor's seventh season. The group are one of the most popular in the world and this was reflected in the turnout of fans at the premiere. Fans were so determined to see their music heroes that some camped out in Leicester Square the night before.

One Direction Fans
Fans waiting next to the red carpet at the premiere of This Is Us.

Styles said the noise of the fans and their sheer numbers as "unreal." Horan added, speaking to a BBC reporter, "this is just unbelievable." Horan continued by saying that the group "made this [documentary] for the fans. We just want to say a massive thank you to them."

Other attendees included Simon Cowell, who co-produced This Is Us and whose show, The X-Factor, the group started out on. On the success of One Direction, Cowell said "I feel like a proud father." Also attending the event were Ronnie Wood, Little Mix (one of whom is Zayn Malik's girlfriend Perrie Edwards), Ulrika Jonsson, Laura Whitmore and Amelia Lily

Simon Cowell
Simon Cowell at the premiere.

The documentary, which was directed by Morgan Spurlock (Super Size Me), is due to be released on August 29th in the UK and August 30th in the US. 

See more pictures from the This Is Us World premiere on Contactmusic.

Amelia Lily
Amelia Lily.

Little Mix
Little Mix - Zayn Malik's girlfriend, Perrie Edwards, is on the right.

Ulrika Jonsson
Ulrika Jonsson with her daughter at the premiere.