Credit: Fotonoticias/

And the "Robsten" speculation heats up even more.

Catherine Hardwicke isn't just the director who ushered Twilight into movie theaters in 2008: she's the woman who helped introduce Robert Pattinson to the world -- and to Kristen Stewart.

In a interview with Time magazine posted online Thursday, Hardwicke tells of a stern warning she gave to her new heartthrob star. "After I cast him, I told Rob, don't even think about having a romance with her . . . She's under 18. You will be arrested." (Today, Stewart is a legal 19 while Pattinson is 23.)

Hardwicke can't confirm whether the pair hooked up while making Twilight, but had close conversations with Stewart about the situation.

"In terms of what Kristen told me directly, it didn't happen on the first movie. Nothing crossed the line while on the first film," she explains.

But the director then adds a tantalizing thought: "I think it took a long time for Kristen to realize, O.K., I've got to give this a go and really try to be with this person."

At London's New Moon premiere Wednesday, Stewart admitted she empathizes with fans who get so emotional around her costar. ""Rob has that magnetism," she said. "it's easy to understand why they're all crazy about him." The pair were photographed holding hands in Paris on Tuesday.