Why Kristen Stewart Should Be Jealous!

Twi-hards, hold your collective breath: The real-life romance between Robert Pattinson and Kristen Stewart — The Twilight Saga’s Edward Cullen and Bella Swan — appears to be heading for trouble. While filming Cosmopolis in Toronto, Rob has bonded in a big way with Canadian actress Sarah Gadon, 24, who portrays his estranged wife in the movie.

Insiders call the relationship platonic, but Kristen, who is back in L.A. preparing for Snow White and the Huntsman, is jealous, especially since Rob gushed about Sarah to MTV. “I’ve seen a couple of things she’s done,” he said of his new co-star. “She’s really good. She has a great face!”

One could say that about most women in the Screen Actors Guild. But it was enough to incite Kristen’s ire. “She was shocked when she read Rob’s quote,” a source tells OK!. “Kristen didn’t want to believe he said it. He apologized, but she still can’t help but wonder if he has a thing for Sarah."

“Kris is smart to keep an eye on it,” the insider suggests. “Rob and Sarah are on set a lot together, and it’s a tight cast — they’re already partying together.”

In the film, Rob portrays Eric Packer, a financial whiz kid and multimillionaire who loses everything over the course of one day and one long limousine ride through New York City’s horrendous traffic. Sarah plays his estranged wife, Elise, a rich and beautiful heiress.

Complicating matters, Kristen and Sarah have a history: Both actresses were up for the lead in Snow White and the Huntsman.

“When Kristen won the role, Sarah was apparently crushed,” the insider says. “So it’s not surprising that she enjoys having something over Kristen.” Like Rob, Sarah is well read — she took part in the Cinema Studies program at the University of Toronto. But perhaps part of the appeal for Rob is novelty — in contrast to the dark, broody Kristen, the bright-eyed blonde has what her friends call a “sunny disposition.”

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