Expect a gaggle of tween girls at the King of Prussia mall today, and not because wide-leg jeans and pencil skirts are on sale.

The stupendously cute Robert Pattinson, star of the new vampire movie,

Twilight

, and inciter of teen hysteria and a near-riot at a San Francisco mall this week, is scheduled to make an appearance.

The mall expected fans to start lining up at midnight to get a chance to meet Pattinson, just as they did elsewhere on his nationwide mall tour to promote the movie, which will open Nov. 21.

Those who aren't up to speed on the vampire/mortal saga should know this: The books by Stephenie Meyer have sold nearly 17 million copies, mostly to preteen and teenage girls who love the dashing and devoted Edward Cullen.

The fact that Cullen is a bloodsucking vampire doesn't diminish the ardor of mousy high school student Bella Swan, who falls for the guy, or whatever, and plans to one day marry him and produce little vampires.

Their chaste relationship is a bonus for many moms, who hope their daughters will likewise save themselves for marriage, though not necessarily marry one of the undead.

British actor Pattinson, 22, who established his heartthrob status as Cedric Diggory, the doomed friend of Harry Potter in two of the films about the boy wizard, plays the literally drop-dead gorgeous Cullen.

Unlike traditional vampires, those in

Twilight

go to a public high school, play baseball, and drive ultrafast sports cars. To fit in, they try to restrict their blood sucking to animals.

Like Bella Swan, hordes of teenage girls are in love with Edward Cullen and his real-life personification, Pattinson.

When the actor appeared Monday at San Francisco's Stonestown Galleria, roughly 3,000 eager fans, nearly 10 times more than expected, pushed to get into the mall. According to reports, several fell under the crush, with one girl injured.

Doors to the Plaza at King of Prussia won't open until 6:30 a.m. At 7 a.m., goth store Hot Topic will start selling $30

Twilight

T-shirts to the first 500 customers, who will be issued wristbands.

At 6 p.m., those with wristbands will be let into the store to meet Pattinson and get an autograph. After the signing, he is scheduled for a public question-and-answer session in the mall.

"Things have been absolutely chaotic around here," said Tyler Shaffer, assistant marketing manager at the mall.

Barriers were erected outside the Plaza between J.C. Penney and CVS, and security was to be on duty starting at midnight for night stalkers who wanted to get a jump on the line. Real fans won't mind 40-degree temperatures and a chance of rain since the books are set in chilly, drizzly Forks, Wash.

After seeing what happened in San Francisco, Shaffer said, the mall planned to have a "substantial crew," including police, to make sure the event went smoothly.

To prevent a mad rush, only 25 people at a time were going to be allowed in the mall to get their T-shirts and wristbands.

Whether thousands will turn out for the Q-and-A remains to be seen. Nonetheless, the mall was "taking every precaution necessary to make this a successful event and an enjoyable event for everyone," Shaffer said.

But if a crush of screaming kids blocking your way has you thinking your patience is being sucked dry - well, what did you expect?