LONDON (August 20, 2013)--Thousands of One Direction fans were gathering Tuesday in London's Leicester Square for the world premiere of the boy band's first feature film.
Some slept in the square overnight to stake out a spot near the red carpet.
"One Direction: This Is Us," a 3-D documentary by "Super Size Me" director Morgan Spurlock, offers a backstage look at the band, which was formed on Simon Cowell's TV talent show "The X Factor" in 2010.
The five-piece group has gone on to top charts around the world and has attracted a die-hard army of fans, known as Directioners.
Band member Liam Payne said the movie was intended partly as a thank-you to the fans.
"One Direction: This Is Us" opens in Britain Aug. 29 and in the United States Aug. 30.