British actor Robert Pattinson, who plays Edward Cullen in the 'The Twilight Saga: Breaking Dawn -- Part 1,' has said he is nervous about how an intimate scene with co-star/real-life girlfriend Kristen Stewart will be received because of fans' expectations.

Referring to the original novel written by Stephenie Mayer, he said: "It's funny, people talk about sex scenes in the book but there aren't actually any. It's all in people's imagination. They're like, 'It's so hardcore.' But it always fades to black. It just shows bits of the aftermath.

"[But] you have to show something! You can't fade to black in the movie because people would go insane!

"It's strange trying to do a singular event which everyone is expecting. At the end of the day, watching other people have sex is never going to be that spectacular. Hopefully, it'll be good. There's so much hype. You're like, 'God, I hope this lives up to it!'"

However, it is not the only scene Robert is nervous about – Kristen's character Bella eventually gives birth to a half-human, half-vampire baby with gory results and the actor says the on-screen labour were "horrible."

He told Total Film magazine: "It was horrible. Insanely graphic and the most nerve-wracking thing about the whole shoot!"