Robert Pattinson doesn't like to repeat his film roles.

The 'Twilight' star ensures that every part he takes on is completely different because he doesn't like feeling ''really self-conscious'' over parts he's played before.

He said: ''I feel like as soon as I repeat myself even a little bit, I suddenly get really self-conscious. If you're pushing something out into the unknown a little bit, you can't judge yourself, because you don't really know what you're doing.

''Even with a voice I can't really do it more than once, because then I think, 'Oh, this is my acting voice.' That's why I can't even do anything in my normal accent, because it doesn't feel like I'm working.''

And the 32-year-old actor felt pigeonholed at the start of his career.

He added to Little White Lies magazine: ''When I first started ... if you're tall and have floppy hair and a posh accent, they're like 'Period dramas!' And then you're exclusively in the period dramas box. I was like, 'No! I don't want to do period dramas!' I've done a couple, and as soon as I put on the high Edwardian collar, I'm like, 'Ughhh'. Your costume is out-acting you at all times.''

Robert previously admitted using a different accent for a movie is ''confusing''.

Asked whether he's able to turn his on-screen accent on and off, he shared: ''It depends who I'm talking to ... if I'm talking to my co-stars, I'll talk to them in my normal accent. If I'm talking to the directors, I'll talk in a different accent. But if it's just before a take or something, I'll talk in this accent. It's all kind of pretty random. I think if you're speaking it the whole time it's quite confusing to yourself ... When everybody is doing different accents, it's very, very difficult to stay in the same one.''