Robert Pattinson has admitted he has a “natural chemistry” with his Twilight co-star Kristen Stewart.

The pair impressed fans and critics as vampire Edward Cullen and schoolgirl Bella Swan in the first film in the vampire franchise in 2008.

"There’s a natural chemistry going on with Kristen,” Pattinson told Total Film magazine.

But, despite the success of the first film, Pattinson said he was concerned about whether their on-screen compatibility would return for the sequel, New Moon.

“Even doing this sequel, it’s so easy…I was really worried that I wouldn’t know how to do it again, but it’s so easy to play off her,” he said.

The 23-year-old British actor also revealed that Stewart often jokes that she was responsible for him being cast as Edward.

He said: “She always says that she pretty much got me the part – though I don’t really believe her!"

New Moon is due to be released in cinemas worldwide on November 20.

Rob and Kristen