Morgan Spurlock, the creator of documentary Supersize Me and director of One Direction's first feature film This Is Us, said filming the band was "the closest thing I'll get in my whole lifetime to seeing anything similar to Beatlemania".
The American filmmaker told The Daily Telegraph: "I actually lobbied for this job.
"This is probably the closest I’ll get in my whole lifetime to seeing anything similar to Beatlemania. The access we got, the stories we tell … I just think it’s remarkable.”
He added: "The goal for me with this movie was to explore why them, why now, who they are, and what got them there. We’re looking at the five of them, and their families, and this amazing ride they’re on".