Actress Mila Kunis has officially finalized her deal to portray the Wicked Witch of the West in Oz: The Great and Powerful.

We reported in mid-February that Mila Kunis joined the cast, although it seems that negotiations just recently ended. The actress will star as Theodorah the Wicked Witch of the West, the youngest of the three witch sisters Glinda, the Good Witch of the North and Evanorah, the Wicked Witch of the East. James Franco will also star as a salesman who ends up in Oz via a hot air balloon which is taken by a tornado. It is said that Mila Kunis' Theodorah starts out as a good witch with her sister Glinda, although she is later convinced to convert to the dark side of the broom.

The other two witch sisters have yet to be cast. It seems Disney is considering such high-profile talent as Olivia Wilde, Kate Beckinsale, Amy Adams, Keira Knightley, and Rebecca Hall for the roles of Glinda and Evanorah.

Sam Raimi will direct from a screenplay by David Lindsay-Abaire. Production will begin sometime this summer.