Fox
Chris Columbus was set to return as director while Williams would have reprised his role as the beloved cross-dressing nanny.
In a statement to Variety, Columbus recalled what it was like watching Williams on screen.
"His performances were unlike anything any of us had ever seen, they came from some spiritual and otherworldly place. He truly was one of the few people who deserved the title of 'genius,'" said Columbus.
Williams previously said a sequel to the film was attempted a trio of times; however, according to the comedian, they could never get the script right.
The original film made more than $441 million worldwide on a budget of $25 million for 20th Century Fox.
Williams still has four films slated for a wide release in the next year, including a third installment to "Night at the Museum" featuring Ben Stiller out this holiday season.
Here's a clip of Williams transforming into Mrs. Doubtfire: