Amanda Seyfried worked herself to the point of exhaustion on the set of her latest movie Red Riding Hood, insisting it was "really tiring" to film in front of a green screen.

The actress was forced to rely on her imagination when shooting the new thriller, inspired by the Little Red Riding Hood fable, as several scary wolf effects were added in post-production.

And the blonde beauty admits her acting skills were put to the test when she had to react to a plank of wood.

She tells US news show Access Hollywood, "(CGI filming) is exhausting and probably the least fun part of my job. I say that because our imaginations are all we have in times like those, but I had to have this certain level of fear that is hard to get when you're not terrified. I had to trick my body into being scared and that was just exhausting."

"I hyperventilated, I (jumped) up and down, and (was) crying, and it's just really tiring, and I'm looking at a piece of wood. I wasn't getting anything. It was all in my head."

"We did have a Styrofoam wolf called Stuffy that was life-sized - he didn't really help that much!"

Source: Press Release