(Cover) - EN Movies - Michelle Williams will play Glinda, the good witch, in Oz: The Great and Powerful.

The movie is a prequel to The Wizard of Oz, and tells the story of how the wizard came to live in the mystical land. The original picture focuses on Dorothy and her dog Toto, who are transported to Oz via a tornado.

The trio of witches are a pivotal part of the story, and it's already known that Rachel Weisz will portray evil Evanora. She is intent on gaining control of Oz and tries to convince her sister Theodora, portrayed by Mila Kunis, to help.

According to Variety, Michelle will play the final witch called Glinda, who rails against her siblings.

James Franco is already lined up to appear, taking the role of Oz. The character sells snake oil, and accidentally travels to the magical land via hot air balloon. He tries to stop Evanora and Theodora, with Glinda backing him up.

The role of the good witch has been highly sought after. Blake Lively was thought to be in the running for a long while, with Lindsay Lohan also hinting she was interested. Further reports suggested it might go to Hilary Swank.

Oz: The Great and Powerful is being directed by Sam Raimi and shooting is scheduled to start in July. (C) Cover Media