1D mania hit London tonight, as chart-topping boyband One Direction attended the world premiere of their film, One Direction: This Is Us.

Thousands of screaming fans, some of whom had camped out overnight, greeted the award-winning group - comprising of 21-year-old Louis Tomlinson, Zayn Malik, 20, from Bradford, and 19-year-olds Liam Payne, Harry Styles and Niall Horan – as they arrived at the Empire cinema in London’s Leicester Square.

Niall said: “This is amazing. We’re really excited to be here. We can’t believe we are here. This is just unbelievable. The last few years have been amazing. This is what we’ve been dreaming of.”

The 3D film, directed by Super Size Me film-maker Morgan Spurlock, is a behind-the-scenes look at the band as they embarked on their mammoth This Is Us world tour.

Styles said the "intimate all-access" film is a love letter to their fans, known as Directioners.

"We made this for the fans. We just want to say a massive thank you to them," he said.
Malik, who took time to pose for photographs with fans, added: "The best thing about our fans is their dedication."

Cowell, who co-produced the film with the group, said: "It has been my dream come true to produce a film. But without their fans, this couldn't have happened. They have the best fans in the world."

X Factor alumni such as Little Mix, JLS, Diana Vickers and Amelia Lily were joined by the show's host Dermot O'Leary and Cowell's right-hand woman Sinitta at the premiere, which was streamed live in other countries.

Rolling Stone Ronnie Wood also attended the event with wife Sally Humphreys.
"I'm proud of my boyfriend but we're really proud of all the boys," said Little Mix's Perrie Edwards, who is dating Malik.

One Direction: This Is Us opens in cinemas on August 29.