If you haven`t heard of "Twilight," ask a teenager. The best-selling young-adult book isn`t bound for the big screen until December, but fan frenzy for the film practically took over Comic-Con on Thursday.

Hundreds of teens camped overnight outside the San Diego Convention Center for a chance to see early footage of the film and get a glimpse at the cast of heartthrobs set to bring the teen-vampire tale to life.

"You don`t understand it until you`ve read it," said 17-year-old Syena Sarrafpour. "The cast of amazing people — they`re hot — obviously adds to the excitement."

She and her friends wore homemade T-shirts touting their love for Edward, the vampire hero who falls in love with a human girl.

"It`s a really good love story that has fantasy," said Emma Quan, 18. "It`s like `Harry Potter` plus romance plus good-looking people."

Thousands of fans — many in homemade shirts proclaiming their preference for Edward or his love-rival, Jacob — filled the convention`s largest exhibition hall, drowning out the cast introductions with enthusiastic, high-pitched screams.

"Oh my God, Robert Pattinson is so hot," said 17-year-old Jenna Barazsu. "I love him. He`s perfect for Edward."

Pattinson, 22, said he was overwhelmed by the attention the role has brought him.

"It`s kind of terrifying in a lot of ways," he said in an interview. "I still can`t really come to terms with it... As soon as one person started to recognize me, literally now I`m just freaking out the whole time."

The British actor previously appeared as the doomed Cedric Diggory in " Harry Potter and the Goblet of Fire" and "Harry Potter and the Order of the Phoenix."

But it wasn`t just the boys who generated buzz. Fans were just as excited to see Kristen Stewart, who plays the story`s heroine, Bella Swan.

"Everyone wants to be Bella," said Sarrafpour. "And (author) Stephenie Meyer wrote Edward as like the perfect guy."

Meyer, who followed up "Twilight" with three other best-sellers, said her main character, a "typical teen," is key to the series` appeal.

"There are so many girls out there who do not know kung fu, and if a guy jumps in the alley they`re not going to turn around with a roundhouse kick," Meyer said. "There`s a lot of people who are just quieter and aren`t having the Prada lifestyle and going to a special school in New York where everyone`s rich and fabulous. There`s normal people out there and I think that`s one of the reasons Bella has become so popular."

"Twilight," a Summit Entertainment release, is slated for release Dec 12.