Robert Pattinson, who stars as the vampire heartthrob Edward Cullen in the forthcoming movie "Twilight," stepped onto a riser at the King of Prussia Mall outside Philadelphia on Thursday evening in front of more than 1,000 mostly teenage girls.

KING OF PRUSSIA, Pa. — Robert Pattinson, who stars as the vampire heartthrob Edward Cullen in the forthcoming movie “Twilight,” stepped onto a riser at the King of Prussia Mall outside Philadelphia on Thursday evening in front of more than 1,000 mostly teenage girls.

The resulting din, in collective pitch, may have approached Beatles-at-Shea-Stadium loud, replete with the weeping, swooning and self-hugging. All of it was over a mostly unknown British actor who plays a character in a movie that will not be released until Friday.

“What is with all the screaming?” Pattinson asked when he came out. He absently ran his hand through his hair. Pandemonium ensued.

Then Pattison smiled: A girl in a “Team Edward” shirt fell into the arms of her friend. “I can’t stand it!” she said.

Along with other members of the “Twilight” cast, Pattinson is touring malls across the country this month. It’s not so much to gin up interest in the film but to feed the monster it has already become. For his Thursday appearance, fans arrived outside the mall the night before to get a ticket.

“Twilight” comes to movie theaters with a long and profitable back story in print: four novels and 17 million copies sold. Written by Stephenie Meyer, 34, the series originated with a dream she had about a young woman and her love for a vampire, who returns her love while managing to avoid his urge to bite her.

The books that followed take place in Forks, Wash., where the Cullens, a group of sun-shirking vampires, live among humans but do not prey on them, drinking animal blood instead. Bella Swan (played by Kristen Stewart), a shy young woman, is drawn to one of them, Edward, even after she comes to understand the danger.

So you have your against-the-odds teen love, your woman in peril, your vampires and your cult following, but “Twilight” frenzy still has the capacity to shock. Last Monday there was a huge crush outside a mall near San Francisco, and a girl ended up with a broken nose. When Pattinson appeared in New York the week before, one young fan asked him to bite her.