Variety's Marc Graser tweeted this evening quite plainly: "Emma Watson has decided NOT to star in Disney's CINDERELLA." No reason for her exit, but it's another bump in the road for Disney, who eager to get this movie in front of cameras this fall (and perhaps double eager following in the massive success of "Oz The Great And Powerful"). The film has already gone through one director, with Mark Romanek exiting the movie over differences about his cash and his vision for the movie. And while Kenneth Branagh is now set to direct, with Cate Blanchett still on board as the villain, the hunt is still one for the young lead.
No reason has been given for why Watson passed, though maybe she thought one princess-esque role in the upcoming, and presumably still happening, Guillermo Del Toro produced "Beauty & The Beast" which (last we heard) is aiming to shoot this summer. He's been attached to direct, but in recent updates, the movie seems to have fallen off his plans, so we could see him tasking it to another filmmaker while he puts his Guillermo Del Toro Presents stamp on it. We'll see what happens with that, but Watson won't be Cinderella at any rate.