'Twilight's Eclipse': Kirsten Prout is Lucy

Kirsten Prout, who showed off some martial arts skills in "Elektra," will wield powers of a different sort ... as a vampire.

The 19-year-old has been cast as Lucy in "Eclipse," the third installment of the "Twilight" series, reports E! News.

Spoiler alert. If you haven't read the books, stop reading now.

The third book focuses on a growing group of newborn vampires, courtesy of Bella's (Kristen Stewart) vamp archenemy Victoria (Bryce Dallas Howard). Jasper (Jackson Rathbone) is the key to defeating this danger because he once had a hand in building up a vampire army of his own.

You see, in Jasper's past, around the time of the Civil War, he was turned into a vampire by Maria (Catalina Sandino Moreno) and helped her create an uber army of "baby" vamps with incredible strength. Among their group was Lucy (Prout), whom Jasper eventually kills.

Prout is best known for playing the piano-playing girl next door Amanda on ABC Family's "Kyle XY."

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