Yeah, it was based on the long-running play.
Here is a pitch meeting for the movie. Or rather, what one guy imagined the pitch meeting might have gone like:
Basically the thinking probably went something like this:
"Maybe it exists in the right medium right now and we don't have to try to squeeze a movie out of it, we could just let the art be..."
"The musical made four billion dollars!"
"I mean we have to try to squeeze a movie out of that, for sure!"
"I thought so too."