Oscar nominated director Morgan Spurlock explains his reasoning behind making boyband movie.

 (SONY PICTURES RELEASING) -  The world premiere of 'One Direction: This is Us' in London on Tuesday (August 20) saw thousands of screaming fans greet the boyband in scenes not dissimilar from Beatle-mania.

Spurlock made his name from his humorous take on corporations, but in 'One Direction: This is Us' he follows the boyband from their beginnings through to their sell-out world tours, covering their style, their dance moves (or lack of), and what they get up to on their travels.

When he was announced as being at the helm on the One Direction documentary project, there were a few raised eyebrows in the movie industry but the director explains that he never had any doubts about getting on board.

"As a documentary film maker, opportunities like this don't come along very often, to have access to a band of this magnitude at this moment, to do a film with a studio. I tell people all the time that 'Listen! You've got to understand. The day this movie opens that it's going to be seen by more people on more screens in more cities in more countries around the world than have seen every movie I've ever made in theatres combines, so as a film maker, why wouldn't you want to make a movie like that?" He said.

Spurlock followed the band around the world and found out first hand their struggles in the world of musical superstardom. He explained: "The hardest part for them which I think you start to see come across in the film is maintaining normalcy, trying to continue to stay true to who you are, your friends, your family, keeping those connections real, and I think that one of the things that's happened to them that's enabled them to do that is that each one of those guys has four other people to keep him grounded, to knock him off the pedestal if you start getting cocky and get too big for your breeches."

"The reason that they haven't had one of these Bieber-esque moments is that they have this support group, because you've got to think when they get off the stage, or if somebody is dealing with something, they each know what the other guy is going through because they're in the bubble with them, they're all in this together. So they know the stress, they know the pressure, they know the tension, they know the timetables they're under, the amount of things they have to accomplish. These guys work incredibly hard from the minute they get up to the minute they go to bed whether it's doing interviews or having to work in the studios or doing a show, it's de-de-de-de their whole day is plotted out," he added.

The documentary maker insists he had full editorial control over the movie. However, there were times when he felt he couldn't film. "There were one or two times where they were dealing with some personal matters that they didn't want us to film but that was few and far between. We shot band meetings, where they were voting on everything that they do. That is one of these things that people don't realise and this didn't even make it into the film which is a shame is that they vote on every decision that happens. Simon Cowell's not pulling the strings deciding what the band does. They vote on are they adding more dates to the tour, where do they tour, are they going to do the stadiums next year, are they going to do matinees, are they going to have this company promote their tour and they vote on it, the five of them, three votes wins. It's an incredible thing. Thank goodness there's not four of them in the band."

The director was lined up to make both Justin Bieber's movie "Justin Bieber: Never Say Never" and Katy Perry's "Katy Perry: Part of Me", but turned down both of them. Explaining why he's so often put in the picture for pop music documentaries, Spurlock said "I'm fascinated by the music business in general. I think the music business has gone in such a different direction that to have this band that exploded and became so successful because of social media and the impact of the fans. You know, the fans made these guys like that - so quickly - and continue to be the driving force behind their success and what I love is that they appreciate that."

Now that his current journey with One Direction is almost over, Morgan Spurlockhas a new project he wants to work on. "The goal is to come out of this film and start doing a narrative film - knock on wood!" he said.

"One Direction: This is Us" goes on release in the UK on August 29th.