'Oz: The Great and Powerful' sequel already in the works at Disney

With "Oz: The Great and Powerful" on track for the biggest box office debut of 2013 so far, Disney is already formulating plans for a sequel.

Variety reports that writer Mitchell Kapner ("The Whole Nine Yards") has been hired to work on a screenplay, but details on the plot remain strictly under wraps. It's unclear whether or not "Oz" cast members including James Franco, Michelle Williams, Mila Kunis, Rachel Weisz and Zach Braff will be asked to return. Kapner is credited as a writer on "Oz" along with playwright David Lindsay-Abaire.

Disney's "Oz" is a sort-of-prequel to the 1939 classic "The Wizard of Oz," and both films were inspired by the work of author L. Frank Baum. Baum wrote 14 fantasy novels set in the Oz universe, so Disney could move in many different directions with a follow-up.

Disney is bullish on live action fairy tales at the moment. Projects in various stages of progress at the studio include "Maleficent," "Cinderella" and "Alice in Wonderland 2."