If you haven't seen it yet, check out the 2013 short horror movie Lights Out below.

Director David F. Sandberg won a short film festival for the movie, and it instantly caught the attention of Hollywood.

From there, the idea was snapped up, and Sandberg has been brought on Warner Bros. to direct the feature length version.

Maria Bello, Teresa Palmer and Billy Burke join the cast of the movie, all finding themselves being tormented by a demonic presence that only appears in the absence of light.

Prepare to be terrified when the lights go out in your local cinema from August 19th.