Schwartz, who was interviewed at the opening night of the new Broadway musical If/Then, said that a timeline was still not in place for the film of his Broadway blockbuster, but that work was underway on the project. "We're starting to do some work on it. We've actually started gearing up on it a little bit," he said.

Schwartz, who collaborated with book writer Winnie Holzman on the musical adaptation of Gregory Maguire's prequel to "The Wizard of Oz," said that the team was also exploring how the stage property would be expanded and adapted for screen.

"What are we going to change? What are we going to keep? How do you use a whole new language and medium to tell the story? [We can] really look at it again and say, 'Oh, we can do this, and we’ve always wanted to do that and we couldn’t onstage, but we can in a movie.' We're actually having a blast," Schwartz said.

He also updated Vulture on the progress of his once Broadway-bound musical Houdini, which was in development as a vehicle for Hugh Jackman. The Tony Award-winning stage and screen actor departed the project in December 2013, and the musical is currently on hold.

Schwartz commented, "I think he didn't really understand, to be perfectly honest, how much work a brand-new musical takes. Every show he's ever done, whether it's been a musical or a straight play, has been a show that somebody else has done … When he suddenly looked at the fact that he has this other career, it just became impractical for him, frankly."