Traipsing around Philadelphia on a rainy November afternoon, Robert Pattinson would most likely fit in with any other 20-something city dweller, in a white T-shirt under a black blazer, black jeans and classic black Nike track sneakers.

However, his recent visit to the City of Brotherly Love was under circumstances far from normal.

Traveling the country on a “Twilight” promotional tour, hordes of teenage girls – and many of their mothers – have flocked to see the young British actor.

Pattinson stars in the upcoming film based on the best-selling novel by Stephanie Meyers.

Only a day away from hitting theaters, the anticipation for the big-screen adaptation has been escalating for months.

“Twilight” tells the story of a young couple separated by supernatural circumstances.

After moving to a small Washington town, Bella Swan is instantly captivated by her classmate Edward Cullen.

Unbeknownst to Bella, Edward and his family are vampires who have disciplined themselves to feed on animal blood, the equivalent of a “vegetarian” vampire lifestyle.

Despite Edward’s efforts to repel Bella and protect her from the complexities of his lifestyle, the two cannot keep apart.

Bella soon finds herself caught up in the vampire world and faces the danger that comes with it.

Pattinson established his heartthrob status after portraying Cedric Diggory in the fourth installment of the “Harry Potter” series.

He auditioned for the role of Edward Cullen in 2007 but did not expect he would be chosen for the part.

While fans of the novel initially objected to the casting, their reaction has completely reversed.

“I can’t go to shopping malls where large groups of teenage girls are anymore,” he says.

Before auditioning, Pattinson had not read the “Twilight” series. To prepare for the role, Pattinson traveled to the Oregon filming location two months prior to any other cast member.

After settling in Oregon, he began reading the books and the script obsessively to prepare his interpretation of Edward.

“I like the idea of there being tons and tons of backstory on this character,” he says. “No one knows what he’s thinking; it makes it interesting to play.”

Pattinson admits that his interpretation of the character differs from what Meyers had imagined.

Pattinson’s Edward is more somber and less suave than the character of the books.

He says he tried to bring realism to the supernatural Edward, drawing upon the complex emotions of the character.

Although 108-years-old, Edward is trapped in the body of a 17-year-old.

Pattinson says he considered all the experiences the character would have seen during his life, albeit through the lens of a teenager, when portraying the character.

After living for years in solitude, Edward finds something to live for in his affection for Bella.

Pattinson feels the strong chemistry he shared with co-star Kristen Stewart successfully transferred the love affair onto the screen.

“There was a very palpable energy,” he says of the relationship between himself and Stewart.

To achieve the physically gaunt appearance of an undead vampire, Pattinson disciplined himself to partake in daily physical training sessions while living on his own in Oregon.

The physical training proved helpful, and Pattinson completed many of his own stunts in the film.

“Doing five hours in the gym each day, my friends thought it was amusing,” he says. “I had literally never been to the gym before.”

Between filming “Twilight” and doing promotional tours, Pattinson has only spent a few days this year in his native England.

Most recently, he has been touring malls across America in a promotional tour affiliated with clothing retailer Hot Topic.

An appearance at the King of Prussia Mall on Nov. 13 brought an estimated 8,000 fans to the store with hopes of meeting the star.

Pattinson, however, says he is still puzzled by the overwhelming reaction the character generates in fans.

“I asked what they see in Edward, why they’re attracted to him,” Pattinson says of a Chicago fan event.

“The unanimous response was, ‘Because he’s so sexy!’ That was the depth of the attraction. I was kind of baffled by the whole thing.”

Delving deeper into the fan reaction, Pattinson says he sees connections between Meyer’s character and male figures in Romantic literature of the nineteenth century.

“He fits the male ideal: Mr. Darcy, Heathcliff, Edward Cullen,” he says.

“Twilight” opens in theaters tomorrow.