Freddie Highmore and Sarah Bolger have been cast as the three Grace children in the fantasy film "The Spiderwick Chronicles," which Paramount Pictures and Nickelodeon Movies will been shooting Sept. 12 in Montreal.

Mark Waters will direct the film from a screenplay by John Sayles based on the best-selling series of children's books by Holly Black and Tony DiTerlizzi. In the movie, the three Grace children move to the ancient Spiderwick mansion, where they discover Brownie, an enchanted creature who introduces them to a world of goblins, fairies and sprites.

Highmore will play the dual role of the troubled Jared and his bookish twin Simon. Bolger will play their sister Mallory.

Highmore, who has appeared in both "Finding Neverland" and "Charlie and the Chocolate Factory," and will be featured in "A Good Year" for director Ridley Scott and take the lead role of "August Rush" for director Kirsten Sheridan. Bolger, who appeared in "In America," will next been seen in Geoffrey Sax's "Stormbreaker."

The film is Kennedy/Marshall and a Mark Canton production.