Morgan Spurlock, the creator of documentary Supersize Me and director of One Direction's first feature film This Is Us has told ITV London that he believes the film is set to be a "doc-buster".
Spurlock said the band's followers were on as "epic scale" and was "beyond his comprehension".
One Direction band members Harry Styles and Niall Horan have told ITV London that they felt a sense of "responsibility" towards their fans as their "role models", adding that they "hoped to do it justice".
One Direction fans have started to camp in Leicester Square, London, in a bid to get a glimpse of their idols at tomorrow's world premiere of This Is Us.
One Direction told ITV News that although being compared to The Beatles was "very flattering" it was "not necessarily something we agree with".
The hysteria surrounding Harry, Niall, Zayn, Louis and Liam was compared to Beatlemania in the 1960s by This Is Us director Morgan Spurlock.
However, the boys dismissed the claims, saying the Liverpudlian foursome were "in a league of their own" and "much cooler than us".
One Direction star Liam Payne said making the boyband's first feature film This Is US was "nerve-wracking" but there could be a follow-up if it is a hit.
Payne said: "I think at the moment we just want to see how this one goes to be honest with you.
"It's so nerve-wracking making the film and stuff. I was thinking the other day when we sit in the premiere and everybody is actually watching it on the big screen it's going to be amazing but I don't know, maybe we'll see how this one goes, see if people like it."
One Direction members Niall Horan, Louis Tomlinson and Liam Payne are in London today promoting their new film This Is Us. The 1D artists said they "can't wait" for it to be released.
Can't believe it's #TwoYearsOfWhatMakesYouBeautiful and this week we premiere our movie This Is Us thank you!
Great to be back with the lads today! Can't wait for the movie :) x
One Direction were left stumped when a journalist asked them what a fan should say to their partner when trying to convince them to watch their new film This Is Us.
After plenty of thought from Harry Styles, director Morgan Spurlock stepped in and said "if he really loves you, he will go to the film".
One Direction's Zayn Malik said the band are not thinking about pursuing an acting career despite the release of their first feature film.
The documentary, directed by Supersize Me creator Morgan Spurlock, follows the five boys, Zayn, Niall, Louis, Harry and Liam, as they travel around the world.