5. Mila Kunis
Earlier this year Mila Kunis played her most complex and problematic role yet as the witch Theodora in Sam Raimi's prequel to The Wizard of Oz, Oz The Great And Powerful. After feeling her love is unrequited by the man she loves, Oscar Diggs (James Franco), the magician from Kansas who finds himself in the magical land of Oz, Theodora turns in to the Wicked Witch of the West from the original film. Her transformation in the film from the innocent but dark-on-the-inside Theodora to the wicked and vengeful character we all remember is different from that of Harleen's transformation in to Harley- but both of these dual roles require an actress who can play two opposing sides of the same character, and I think Kunis is that kind of actress. Kunis' performance in Oz displayed her dramatic capabilities as an actress and revealed she could be effective in a villainous role. She was also able to communicate the tragic nature of the Theodora character, which will be important in playing Harley, a good person whose mind has been twisted due to her bizarre relationship the Joker.