But one of the most exciting changes from last year's "Twilight" is purely visual in nature: shooting the third act of the film on location in Italy.
"Wow, am I glad we were able to shoot there," Weitz said with a laugh in a recent phone interview with MTV News. "We went to about 12 different hilltop towns in Tuscany, which was both delightful and exhausting, because it had to be done relatively quickly. Montepulciano had the most symmetrical main square that I could find, so that was the winner for that reason."
Fans can expect about 20 minutes of the film to be spent in Italy or in interior shots set in Italy. While trailers released for "New Moon" show hints of flashbacks featuring the Volturi, Weitz said most of the time is dedicated to the present day.
The use of color in the film is a big change from "Twilight," especially with the striking use of red shown in the trailers during a festival in Italy.
"We took out a lot of the cold, blue tones of the first movie to begin with. But the golden quality and the red, which we had sort of purposely saved in terms of our production design and our costume design, came out in Italy," Weitz said. "We actually planned it so there were very few occurrences of the color red. It's very rare in the beginning of the film. And then, suddenly, you're sort of punched in the eye with this burst of red when Kristen [Stewart]'s character arrives in the main square."
Weitz said the changes in color don't end with the contrast between Forks, Washington, and Volterra, Italy. He gave a play-by-play of some of the Italy scenes to show how they used aspects of light and dark to their advantage.
"Bella runs and gets Edward, but no sooner have they done that then the big, bad guys show up," Weitz explained. "And then they're in the dark again, taken through these subterranean tunnels, and then you go to the — for want of a better expression — bad-guy headquarters, but instead of it being a dark, kind of Dracula's-castle place, it's actually surprisingly light and crisp. We just sort of wanted to play interesting games with color and light."
The "bad guys" are another big change from "Twilight." In addition to continued baddies Victoria (Rachelle Lefevre) and Laurent (Edi Gathegi), veteran actors Michael Sheen and Dakota Fanning joined the fray as two members of the Volturi: Aro and Jane. Both actors got a chance to play something new. For Sheen, it was a chance to play a vampire, versus the werewolf he had played in the "Underworld" series.
"He is one of those extraordinary British actors who is adaptable to any circumstance and who has not a millimeter of ego," Weitz said. "Michael kind of approached this role — not as a gag but thought, 'Well, what would a 2,000-year-old vampire be like?' "
For Fanning, it was the chance to be the bad girl for once.
"She's never really gotten to play a bad person before, probably because she is a very good person. She is really a lovely young person. But I think she had some fun playing, really, the most evil of all the bad guys," Weitz said. "[Jane]'s bad news. Very bad."
For more from the "New Moon" cast and to see an exclusive clip from the film, check out MTV's "Ulalume: Howling at New Moon" on Friday, October 30, at 9 p.m. ET — and check MTV.com at 10 p.m. to see the clip exclusively online!
Check out everything we've got on "The Twilight Saga: New Moon."