Robert Pattinson believes that the secret behind the phenomenal success of 'Twilight' saga is that it teaches teenage girls that abstinence can be sexy.

The movie franchise, adapted from Stephanie Meyer's best-selling books, is about a young girl who falls in love with a vampire. Meyer, a Mormon, does not believe in sex before marriage.

The 23-year-old British actor, who plays vampire Edward Cullen, is of the opinion that the chaste relationship between the two lead characters is the secret of Twilight's appeal, the Telegraph reported.

He and Kristen Stewart, who plays schoolgirl heroine Bella Swan, share no more than a kiss in the first three books.

"The success of the Twilight books comes from the fact that fans can lust after Edward and yet, certainly in the first book, there's no actual sexual contact between him and the series heroine.

"Twilight is a big metaphor for sexual abstinence, and yet it's erotic underneath. There are so many elements in the story which are sexy," Pattinson said.

The actor, who played a brief role as Cedric Diggory in the Harry Potter films before being cast in the 'Twilight' series, became an overnight sensation post the international success of the movie.