She’s not “adorable little Dakota Fanning” anymore. She’s 16 now, but you’d never know it by talking to her on the phone. In a recent interview from Los Angeles, where she was promoting “The Twilight Saga: Eclipse,” which opens Wednesday, Fanning came across as every bit the seasoned film and TV veteran she is — some 40 movie and TV credits since her debut, at 5, in a Tide commercial.

On the phone, she seems, well, perhaps 26. The Georgia native is polite, charming, intelligent. She does not giggle. We talked briefly about her role as one of the Volturi, the ultra-nasty vampire royalty who make brief appearances in both “Eclipse” and its predecessor, “New Moon.”

Q. What are the Volturi up to this time?

A. We come there (the U.S.) this time, rather than everyone coming to Italy. There’s a big battle between the vampires and the werewolves on one side, and the newborn vampires on the other. The Volturi kind of pop in, do their thing and swoop out. (Not wanting to give too much away, she declines to define “their thing” for publication.)

Q. Those red eyes are wicked. How do they do that?

A. We have hand-painted contact lenses. They were really hard to get used to at first, but once you put the costumes on and those contacts in, it’s very dramatic in terms of acting. You transform.

Q. You look very Old Hollywood in photographer Norman Jean Roy’s Vanity Fair “Women of Twilight” layout in the July issue. What was shooting that like?

A. Magical. Wonderful. It’s such a cool magazine, and it was so glamorous. Everyone looked gorgeous. (Also in the layout are Ashley Greene, Elizabeth Reaser, Nikki Reed, Julia Jones and Bryce Dallas Howard.)

Q. Kristen Stewart, who plays Bella in the “Twilight” films, has a reputation for being sullen. True?

A. Kristen has become one of my best friends (the two also appeared together in “The Runaways”), and she’s one of the most fantastic, lovely people I know. She’s one of the greatest friends you could have. Kristen’s not sullen. She’s just so passionate about what she does; she wants to give it her best all the time. She takes everything to heart, and she comes across as serious.