Mandy Moore was supposed to star in Safety Glass

The role that Hilary Duff is playing in her upcoming movie Safety Glass was originally supposed to be played by Mandy Moore. It isn't clear if Mandy Moore had an official contract in place or anything, but several of her fan sites like this one were discussing her role in Safety Glass as far back as 2005. I couldn't find anything about why Mandy didn't continue with the project, but I suspect that she either got too tired of waiting for the film to start shooting, or simply became too old to play a high school student.

Original reports of the casting for Safety Glass also included Michelle Williams and Amber Tamblyn. As far as I can tell Michelle Williams is off the project now, and I think that Tamblyn is off also (although she is still listed on IMDB). I believe that Tamblyn was replaced by Olivia Thirlby who recently gained notoriety by starring alongside Ellen Page in the Academy Award Best Picture nominated movie Juno.