That Fanning made such an impression with so little was, well, impressive. In contrast, Cameron Bright, another seasoned child actor whose credits include X-Men 3, Thank You for Smoking, and the creepy-kid flicks Godsend and Birth, had next to nothing to do as Jane's twin and fellow Volturi guard, Alec. (Sadly, this probably comes from Alec's presence, or lack thereof, in the book.) But Bright is already growing out of his kid roles, so by the time a Breaking Dawn film becomes reality, we hope his part gets juicier.

Then again, the real star of the Volturi is Aro. Michael Sheen, who ironically played the vampire-hating werewolf Lucien in the Underworld series (below right), is a terrific addition to the cast. Dressed in a fine Italian suit, circa 1980, Aro wears his hear in a slick ponytail and wears gold necklaces. His Aro is a sinister villain; welcoming on the surface, but clearly calculating, unpredictable, and off-putting.

"I love the thing in the books that Stephenie wrote about how these vampires are all really beautiful, and that's what lures people into their web," Sheen explained between scenes. "And yet, Aro is not like that; she describes Aro as being not the same sort of thing. I like the idea that it's his voice that lulls people in, or his sort of demeanor, rather than the way he looks -- because he looks quite weird and scary."

"I've tried to go down that route, make him very mesmerizing to people, that his voice is gentle and soft -- and yet, there's something kind of unhinged about him."

It was a single word that gave Sheen the inspiration for his take on Aro. "I read it over and over again, that particular bit in the book, because there are all kinds of things that she says -- like, she describes his voice as being quite feathery -- that's what gave me the idea of making it very soft, and light."

That deceptive lightness is what makes Sheen's Aro so effective. We watched New Moon's pivotal "meeting" scene unfold, as Edward and Alice are forced to bring Bella into the Volturi's nest to meet Aro and the others for the first time.

"What a happy surprise! Bella is alive after all," Sheen exclaims, oblivious to the looks of trepidation on the faces of his new guests. He approaches the trio, arms open, reaching out to sniff Bella's "sweet" blood and to "read" Edward's thoughts. Sheen's eyes blink open with discovery.

"You can't read Bella's thoughts," he announces, abruptly. Sheen turns to Stewart, a gleam in his eye. "I'd like to see if you're an exception to my gifts as well. Would you do me the honor?"

Bella (Stewart) hesitates, looking nervously to Edward before offering her hand. After a moment, Sheen lets out an enormous cackle of amusement. Aro cannot "read" Bella, an anomaly that at once delights and perplexes him. "Interesting," he says. "I see nothing. I wonder...let's see if she's immune to all our powers, shall we Jane?"

Of course, "Jane" is not there. Fanning's already gone home for the day, her scenes shot out of sequence. Weitz plays out the "meeting" a few more times, before calling a wrap on the scene with a polite, "Cut. Thank you."

Behind the stage, huddled around a bank of playback screens, author Stephenie Meyer and screenwriter Melissa Rosenberg have been watching dailies. They giggle at Sheen's maniacal Aro. They marvel at how gorgeous Fanning looks on the screen. Later, Rosenberg tells us what she thought of the footage.

"I've written a lot of hours of television," she began. "I'm almost always disappointed; not because I don't have great, great directors but because you get in your head what you see, you know? A director can't physically do what's in my head because it's not physically possible."

But when it came to the Volturi scenes we'd just observed, Rosenberg seemed almost surprised. "Oh my God, it's fantastic," she shouted. "The cast is phenomenal!" (Stay tuned for our full posting of our chat with Melissa Rosenberg.)

Next: How you'll get your Edward Cullen fix in New Moon (despite his absence), and Melissa Rosenberg on how changing some things from the book makes it more faithful