Rupert Grint was "overwhelmed" by his role in Knock at the Cabin.
The 32-year-old actor takes on the part of Redmond in the new horror - which sees a family of three held hostage by four strangers whilst on holiday in a remote cabin - and admitted that he "relished" in the "intensity" of the job even though he was unable to sneak away from the small set.
He said: "It's definitely something you relish, it's quite overwhelming when you first touch the surface. It's quite intense and there's nowhere to hide. It was quite a small cabin and I was constantly in this mindset. Usually you kind of sneak off and do your own thing but I couldn't do that on this and it was very intense.
"The characters have a very specific role and it's very bleak. It is very heavy stuff. In between takes, we had to keep it kind of light-hearted because it is very heavy stuff.
The Harry Potter star - born in Harlow in Essex - has had to feign an American accent for the part and went on to explain that he "couldn't keep it up" between takes and had the urge to put on a Southern drawl whilst on camera.
He told HeyUGuys: "Yeah, I can't keep it up. I had to come out of it. It is definitely a muscle you have to keep working. Weirdly, with Redwoods, I don't know what it was, but I had this urge to be Southern so that was always creeping in. So yeah it was something I always had to work on but it kind of further immerses you into the world!"
Knock at the Cabin is showing in cinemas now.