In a Premiere magazine interview, Robert Pattinson says fans will be shocked by the gory birth scene in the "Twilight Saga: Breaking Dawn - Part 1."

The actor, who portrays the vampire Edward Cullen, said his girlfriend Kristen Stewart looked like an alien when playing Bella Swan during the shocking scene. He warned that fans will be surprised how graphic the movie is going to be.

"It's hilarious. No movie this size dares taking those kind of risks," Pattinson explained as he spoke to Premiere magazine about the scene where Bella's baby eats her from inside.

"But since the craziest scenes are a big part of the story going forward, it was impossible to not have them included in the film. There was no way we would tone it down," he continued.

Pattinson went on to say the director of his latest film "Cosmopolis," David Cronenberg, will be stunned by his portrayal of vampire Cullen in "Breaking Dawn."

"I think he's going to enjoy certain scenes, like the one where I open Kristen up by biting through her placenta," the actor claimed. "It was without a doubt the funniest thing I ever had to do. I'd raise my head up and I was covered with cottage cheese or whatever substance they put in there."

Pattinson added that when it came to shooting the scene, they wanted to make it as realistic as possible. "Before filming the scene, ['Twilight' author] Stephenie Meyer, a midwife, Kristen and I sat down to talk to a doctor to decide where I was supposed to bite if this situation would ever occur in real life," he told Premiere. "The doctor looked at us a bit puzzled and said I don't think you could ever do this in real life."

"The Twilight Saga: Breaking Dawn - Part 1" is due to hit cinemas this November.