God Help the Girl has been written and directed by Stuart Murdoch and will premiere on August 16 in UK cinemas after a screening at Edinburgh's Corn Exchange with the cast in attendance.
Murdoch, who will be playing songs from the film in a live concert after the film premiere in a gig which will be broadcast by satellite to other cinemas, said he was unsure if he will make another movie.
The coming of age film set in Glasgow over one summer stars Emily Browning, Olly Alexander and Hannah Murray and was produced by the twice Oscar-nominated producer Barry Mendel.
The movie had its international premiere at the Sun-dance Film Festival 2014 and won a special jury prize.
He said: "Making this film has been a wild trip. When the film was being made it was all hands on deck and then six months of sitting in the dark editing the film, it has included some of the craziest situations I have been involved in.
"Audience reaction so far has been OK - it's had some shaky press, but that is independent cinema: I think it will find its own audience just like my band had to."
"I'd like to make another film but I don't know. I come up with ideas from time to time but for the next year I'm concentrating on the band."
Murdoch revealed he had changed his mind about the independence referendum in Scotland, and now supported independence
He said: "Basically after the financial crash in 2008, nothing in the UK seemed to change and becoming a nation seems like a good idea. Folk all over the world love Scotland and its culture and that will never change."