"When I met Rob, I didn't think twice about him," Greene says in new issue of Seventeen, on newsstands May 25. "He's really attractive, but that chemistry wasn't there."
And with what could be a dagger in the hearts of woman all over the world, Greene says the sex symbol "doesn't understand girls."
"He gets a lot of attention from them, but he doesn't quite understand it because before Twilight, he was just a guy from Harry Potter."
But it was different story for Greene and her Twilight costar and onscreen family member, Kellan Lutz. When asked if she's ever hooked up with Lutz, Greene replied, "I've definitely thought about it."
She says the pair, who are currently in contract negotiations to make sure they remain part of the Cullen family for the final two Twilight installments, met years ago through their agent and they've been "best friends ever since – and filming together has made us even closer."
But Greene doesn’t see romance in their future together. "He's one of my best friends, but if we were going to be romantic, we would have done it years ago!" she says. "I like having him to talk to about other guys to get that male perspective. I really cherish our relationship, so I wouldn't want to mess that up by dating."