Kristen Stewart and Robert Pattinson: Test Kissing

Twilight director Catherine Hardwicke had a unique method to determine Robert Pattinson and Kristen Stewart’s compatibility before casting them in the vampire epic: She had them kiss for their audition.

In her bedroom.

The director, who is currently promoting Twilight: The Director’s Notebook, says that she made sure to watch the two swap spit before signing them to the roles of Edward Cullen and Bella Swan.

“[During casting] I did the whole scene in my bedroom to be sure that these two people had sparks,” she tells Life & Style. “Are they intense? Are we going to believe it and love it?”

“I said, ‘Yes, we really want you to kiss. I want to see if this works,'” she reveals. “Because at the end of the day, if it just doesn’t work, then it’s not going to work for the whole movie. So I made them go ahead and kiss, and the sparks did fly!”

Did they ever. Pattinson and Stewart are currently filming Twilight’s sequel, New Moon, in Vancouver.

Hardwicke, however, won’t be a part of the project. She passed on the opportunity to direct New Moon. The director admits that she is “sad” not to be working with the two actors whom she says have managed to remain “grounded” despite the intense media scrutiny.

But Hardwicke shouldn’t feel too bad about bowing out of the series. At the very least, with her unusual auditioning practices, she’s no doubt provided Katy Perry with a few ideas for her Operation Kiss Kristen Stewart campaign.