Ambrose replaces the previously announced Michelle Williams. who The trade mag cited from a production source, who said, "The filmmakers enjoyed working with Williams, but her voice didn't match their original vision of how the Wild Thing should sound."

Jonze adapted the Sendak children's book with Dave Eggers. Warner Bros. will distribute the film for Playtone/Wild Things in association with Legendary Pictures and Village Roadshow.

The feature film adaptation of the tale a young boy's journey into the world of giant creatures will use a mix of real actors, computer animation and live-action puppets. The project is slated to debut in fall 2008.

Ambrose joins a cast that includes Forest Whitaker, Catherine O'Hara and fellow stage veterans Paul Dano (Things We Want), Catherine Keener (Burn This), James Gandolfini (A Streetcar Named Desire) and Tom Noonan (Buried Child). Max Records, Angus Sampson, Steve Mouzakis, Alice Parkinson, Sonny Gerasimowicz and Michael Berry, Jr. are also attached.

The actress — who is set to star in the upcoming Fox television series "The Return of Jezebel James" — played on Broadway in Awake and Sing! and recently as the title lover in the Public Theater's Shakespeare in the Park run of Romeo and Juliet. A star of HBO's "Six Feet Under," she has also appeared in the films "In & Out," "Can't Hardly Wait," "Psycho Beach Party," "Diggers" and the forthcoming "Starting Out in the Evening" opposite Frank Langella. Sendak recently collaborated with playwright Tony Kushner on a one-act opera take on Brundibar — based on his namesake 2003 children's picture book. The scribe provided production design for the work that featured a libretto by Kushner (adapted from Adolf Hoffmeister and Vaclava Klimenta Klicpery) and music by Hans Krasa and Bohuslav Martinu. And his previous work, the musical Really Rosie, featuring music by Carole King with book and lyrics by Sendak, is slated to be revived in spring of 2008 by Atlantic for Kids.