Christopher Heyerdahl was interviewed by Scifiwire (part of SyFy, formerly the SciFi channel):

Word of Heyerdahl's casting in the second of four contemplated films based on Stephenie Meyer's best-selling books caught the attention of his friends. "I have friends of friends who send me e-mails and call me from all over the world," he said. "Every one of these young women feel that this story is about them. It's absolutely remarkable to be a part of something so widespread. It's a once-in-a-lifetime opportunity."

Heyerdahl's character is a member of the Volturi, a venerable coven of vampires based in Volterra, Italy, whose members also include Michael Sheen and Dakota Fanning.

"He's one of the oldest vampires on the planet, and who doesn't want to play a 3,000-year-old vampire?" Heyerdahl said. "The cast that I get to work with, like Michael Sheen. ... We had so much fun goofing off together. It was an absolute hoot. Director Chris Weitz's version for this piece is like a Renaissance painting. The images were absolutely beautiful, and the character is such a tragic old fellow."

Check out the rest of the article, it's very interesting!