The 24-year-old actor, who plays vampire Edward Cullen in the franchise, said that he is worried that the film will be classified as too scary for younger fans.
He told Entertainment Weekly that there will be, 'some interesting and weird stuff going on.
'It's really very, very, very strange.
'It's great. For a big mainstream movie, it's the most obscure storyline and really outside the box. It's a horror movie.
'I just can't see how it's going to be PG-13... unless they cut everything out.'
The first instalment of Breaking Dawn is scheduled for a November release.