Kristen Stewart may
be finding Robert Pattinson's latest movie, Remember Me, extra hard to forget. On June 19, Kristen's new beau spent the morning making out with his leading lady, Emilie de Ravin, while watching the waves roll in on a deserted beach in New York's Far Rockaway, Queens. Even though they were shooting scenes from the romantic drama, "they both seemed to be having a great time and looked genuinely happy to be working together," says an onlooker. "Emilie and Rob looked really cute!"

Their instant bond is heartbreaking for Kristen, who fell for Rob when they shot Twilight and its sequel, New Moon -- and eventually split from her longtime boyfriend Michael Angarano to be with him. "Rob flirted with Kristen when they were filming," says a Twilight insider, "so she can't help but wonder what he's doing with Emilie."

For more on the drama between Kristen and Rob, pick up the latest issue of Life & Style Weekly, on newsstands now!

Photo Credit: Retna