Oscar-nominated actress Michelle Williams is in talks to join the cast of Sam Raimi's Oz: The Great and Powerful. She will portray Glinda the Good Witch, rounding out the trio of witches including Theodorah (Mila Kunis) and Evanorah (Rachel Weisz).

Last month, we reported there was a potential power struggle between Disney execs and director Sam Raimi over the casting of an evil witch in this drama. The director insisted on casting Hilary Swank, although the studio opposed this and wanted Michelle Williams for the role. Since Mila Kunis had already locked in the Theodorah part, it was believed they were fighting over the Evanorah role. However, a few weeks later, Rachel Weisz began talks for the Evanorah role, and now Michelle Williams will play the good sister, Glinda.

Sam Raimi is directing Oz: The Great and Powerful from a screenplay by Mitchell Kapner and David Lindsay-Abaire. Production is scheduled to start this July in Michigan.