Doctors Try To Find 1D Fan Gene In 'This Is Us' Movie

One Directionare on a quest to find out what makes their diehard fans love them so much.

This Is Us director Morgan Spurlock has revealed that the lads visit a doctor in the 3D concert flick to find out what makes female fans tick and to discover what makes people a Directioner.

Speaking to the New York Post, Spurlock revealed: "We ask the question 'Why Them?' We talked to this one doctor who tells us what happens inside a girl's body when she hears One Direction – like what happens in her brain and what goes on inside of her."

Spurlock previously took part in a Twitter Q&A with fans regarding the film, where he promised lots of topless shots of the lads.

He stated: "There will definitely be a DVD, we've shot so much amazing footage, we're never going to be able to pack it all into one movie.

"There have been some really lovely emotional moments that we've captured, I think fans may shed a tear or two while watching."

This is Us is due to hit cinemas on August 30, with Louis Tomlinson also confirming Directioners can expect their third studio LP in time for Christmas. 

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