Pattinson and Stewart Do a Bogey and Bacall

According to sources of the well-sourced, Robert Pattinson and Kristen Stewart, stars of Twilight and the forthcoming New Moon, are more than co-stars. In the tradition of Humphrey Bogart and Lauren Bacall, Paul Newman and Joanne Woodward and Warren Beatty and Annette Bening, Pattinson's and Stewart's impressive screen physics has led to an off-screen romance, a development that will delight fans of the celebs who equally excite the editors of Tiger Beat and Vanity Fair.

After Catherine Hardwicke, director of Twilight, auditioned actors for the roles of intense Bella and velvet vampire Edward, she told Flickgrrl of the "electric charge" sparked by their screentest. So impressed was Hardwicke by the pair's chemistry -- and physics -- that she issued a warning to Pattinson, then 21, to steer clear of Stewart off camera because she was a minor. Besides, Stewart also had a bf, Michael Angarano.

Kristen Stewart and Robert Pattinsom, the vamp and the vampire

Now that Stewart is 19 and Angarano appears to be out of the picture, the New Moon stars are keeping company. A veteran Hollywood observer might want to tell the couple that for every Bogart and Bacall (or Brad and Angelina or Susan Sarandon and Tim Robbins or Melanie Griffith and Antonio Banderas) who play lovers on a movie set before seguing into the real-life roles, there are Heath Ledger and Michelle Williams, Russell Crowe and Meg Ryan and Ben Affleck and Jennifer Lopez for whom, once off the set, the candle is snuffed by the Santa Ana winds.

Your favorite on-set romance that endured? That didn't? (Thanks to Nick Tarnowski, for his help.)