From PEOPLE Magazine Click to enlarge
So how does Kristen Stewart feel about kissing Hollywood's hottest vampire? "He has the thickest beard," she told PEOPLE last year after shooting scenes with her Twilight costar Robert Pattinson. "You didn't notice until five minutes afterwards, and then you're like, 'Oh, wow. I think I'm bleeding. I think I'm totally raw.'" Still, don't expect her to call for a stunt double. "He's British. He's tall. He always looks like he's thinking about something. And he's quite witty," she said. "So he's pretty sexy."

The feeling is mutual. Officially they're just pals, but even a member of the undead would feel the heat between Stewart, 19, and Pattinson, 23. Still, Stewart has been an elusive quarry. "Rob has been after Kristen since they started filming" the series two years ago, says a production source. After wrapping sequel New Moon in May, the pair spent the early summer on different coasts: she in L.A. filming The Runaways, portraying Joan Jett; he in New York City filming the indie drama Remember Me. But in August they'll reunite to film Eclipse, the third film based on the Twilight books, and friends wonder if their flirtation can blossom into full-fledged romance. "He's a total ladies' man," says a source. "She's unattainable, and that makes her attractive to him."

Turns out the London-born Pattinson, who earned his teen-idol cred as Cedric Diggory in two Harry Potter movies, had his eye on Stewart from the start. He auditioned after seeing the L.A.-bred former child star (she was Jodie Foster's daughter in 2002's Panic Room) in her sultry turn in 2007's Into the Wild. "She's basically the reason I did the movie," he said last year. "When I got in the room with Kristen, there was a certain chemistry." So why didn't they let it combust? Several factors stood in the way. As they began filming Twilight in 2008, Stewart was all business—and serious about actor boyfriend Michael Angarano, 21. Pattinson proceeded to have a fling with costar Nikki Reed. "They were hooking up, but it wasn't anything serious," says a source, adding that Reed broke it off because "he had a thing for Kristen, who is [Nikki's] best friend." Pattinson "plays girls," adds the source.

Set sources say the romantic tension between Pattinson and Stewart grew over time, despite concerns about mixing love and work. "Kristen is hard to read and very dry. She was the one person whose attention Rob couldn't get," says a source. But when the cast headed to Vancouver to film in March, they spent time together playing guitar, going to concerts and spending long nights out at local restaurants. On the weekend after Stewart's April 9 birthday, Angarano was nowhere to be seen, but Pattinson joined her and other castmates for a party at Rodney's Oyster House. (Reps won't comment on whether Stewart and Angarano, who were last photographed together on April 25, are still dating.)

Weeks later, after a concert by Pattinson's musician pal Sam Bradley, Pattinson and Stewart were spotted kissing at Vancouver bar Richard's on Richards. "They were whispering in each other's ear and getting all cuddly," says waitress Alicia Bell. "They were acting like a girlfriend and boyfriend." Since New Moon wrapped, both actors have kept low social profiles. Despite rumors linking him to costar Emilie de Ravin, Pattinson spent his free time with male pals at hipster bars such as Black & White. "Fame came to him very unexpectedly," says an old friend. "He's a really down-to-earth guy who is shy."

But not when it comes to Stewart. "She's the one girl he can't get," says a source. That doesn't mean he won't try. Asked by Ryan Seacrest last year if he could fall for his costar, the fanged heartthrob seemed ready to take a bite: "Oh, yeah—she's amazing!"

  • Contributors:
  • With Oliver Jones/Vancouver,
  • Christine Kilpatrick/Vancouver,
  • Scott Huver/Los Angeles.