Working in front of a massive green screen as hellish BELLTRIX LESTRANGE in the new Harry Potter film made Helena Bonham Carter sick. The British actress admits the make-believe scenes, in which she had to pretend things were flying around her, left her feeling nauseous. She says, "The Hall Of Prophecies where the globes are, that was just complete green space and a just total empty room. And it's pretty horrible. "It's really discombobulating and you can do some really bad acting in green screen. And a lot of time you feel so out of touch and not grounded and actually it's because you're in space and you have no idea what's around you. "It is really throwing and also it makes me feel sick actually that green because it's so bright."