Deadline confirms that Moretz will be playing Carolyn, the teenage daughter of Elizabeth, the reclusive matriarch of the Collins family played by Pfeiffer.  In the original series, Carolyn Collins was a free-spirited nineteen year-old, and Moretz is fourteen, so Burton's younger version will lose some of the swinging sexuality that defined the character on television.

Yesterday, the Speculate-O-Tron went into overdrive when Moretz announced that she had just joined a "huge project".  Many fans immediately leapt upon the possibility that she was referring to Hunger Games, the Gary Ross-directed adaptation of the hugely popular novel by Suzanne Collins.  Phil at Badass, discovered a clue predicting that Moretz would be the next name attached to Shadows, and it turns out to have been on the money.

No word yet on the status of British actor Michael Sheen, who is considering joining Dark Shadows as Robert Collins, Elizabeth's brother and uncle to Carolyn. 

Chloe Grace Moretz has spilled plenty of grown up blood between her two starring roles as a pint-sized murderer Kick-Ass and and an ageless vamprire in Let Me In, but Dark Shadows is her most high profile project yet.  The Tim Burton film is written by novelist/screenwriter Seth Grahame-Smith, who also wrote the screenplay for Abraham Lincoln: Vampire Hunter, adapted from his own novel.  Moretz, meanwhile, will next be seen in Martin Scorsese's first 3D film, Hugo Cabret, due this Thanksgiving.