Has Jennie Garth just all-but-outed Robert Pattinson's rumoured romance with Kristen Stewart?

The 90210 actress and wife of Rob's vampire father figure Peter Facinelli admits the heartthrob is dating one his Twilight co-stars - but refuses to specify which one.

"I can't say (who it is), because that would be breaking my promise (to husband Facinelli), but he (Pattinson) is dating one of them," she dishes to the New York Daily News.

Persistent reports that Rob and on-screen love interest Kristen are a real-life item began in earnest during the filming of New Moon earlier this year, and stepped up a gear after they spent a secretive five days together in Los Angeles last week.

Rob has also been linked to Nikki Reed, who plays Rosalie in the vampire saga, though this option seems less likely than a Rob and Kristen union.

The pair are currently in Vancouver, Canada, with the rest of the Eclipse gang to begin shooting on the third Twilight movie.

Rob, Kristen and co. at the Teen Choice Awards on Sunday