Dylan O’Brien and James Sweeney in ‘Twinless.’ (Lionsgate)

Dylan O’Brien plays identical twin brothers in Twinless.

The new film, which arrives in theaters on Friday, was written and directed by James Sweeney, who also co-stars. O’Brien told ABC Audio the idea of playing identical twins wasn’t something he would have been drawn to if it wasn’t for Sweeney’s script.

It was “a concept that I was really emotionally struck by, telling the story of such a unique experience on this earth and a unique loss on this earth I really found compelling,” O’Brien said.

O’Brien knew he had to be a part of Twinless because he felt like “this could be something so special” where he could really “go on the journey with these characters that I felt such a connectivity to in hands that I trusted so much,” referring to Sweeney.

Sweeney himself is not a twin, though he says, “I am still waiting to be running into a forest one day and bump into it.”

The writer-director-actor said he was always fascinated by the idea of having a twin.

“I think it does represent the soulmate ideal of a best friend who wants to do all the things you want to do, can share the mundanities of life together,” Sweeney said. “Now, having done a lot more research, I understand twin relationships can be very complicated. No twins are alike. It’s not a monolithic experience, but I think there is an inherent beauty in being able to share your life with somebody.”