Before ET airs the never-before-seen 'Twilight' trailer on Tuesday, ETonline has a clip of the new behind-the-scenes footage of the highly anticipated vampire thriller/love story flick based on the New York Times best seller.

In an excerpt from the new footage, which can also be seen on the DVD of the Christina Ricci film 'Penelope' -- on sale Tuesday -- screenwriter Melissa Rosenberg and author Stephenie Meyer chat about the film, in theaters December 12.

And you can also see an actual scene from 'Twilight' on the 'Penelope' DVD.