Popcorn Biz reports:

Fans of the “Twilight” films are going to have a little added story to sink their teeth into.

The previous movie adaptations of Stephanie Meyer’s vamp-lit juggernaut have gone pretty much by the book, but with the final novel “Breaking Dawn” being broken into two feature films, screenwriter Melissa Rosenberg tells PopcornBiz she’s enjoying a little more leeway to add some fangy flourishes of her own.

“I did actually [get to do that], because we got to fill out the story because we're doing the next two movies,” said Rosenberg. “So there was room to play and expand on some of the characters that Stephanie introduces. That was a lot of fun.”

“It's a much more grownup movie – It's an adult story,” the writer said of evolving the franchise beyond its high school origins. “The stakes are raised even higher because it's not the story of teens. It's the stories of grownups, so we're talking about marriage and children and family – and these are pretty grownup things, but sexy.”

If you haven’t read the books, beware of the SPOILER up ahead.

Rosenberg says the highlight of the story will be seeing Kristen Stewart’s character Bella become a vampire at long last. “Kristen gets to make the transformation and that is going to be so exciting to see. [Director] Bill [Condon] and I talked about it in developing this script and the screenplay. Now she's going to embody it. It's going to be so great.”

Rosenberg, who penned all of the “Twilight” films and previously wrote for Showtime’s “Dexter,” hasn’t quite adjusted to the fact that, minus a few rewrites, her bloody good run is coming to a close.

“It's a shocking experience after four years to not be writing ‘Twilight!’” she said.

So what do you think Twifans, should Melissa be making up parts for Breaking Dawn (more scenes as Bella as a vamp, make the fight scene a actual fight) or should she be sticking directly with the book? What would you like to see expanded upon?