It’s originally based on the 1986 British novel “Alias Madame Doubtfire” by Anne Fine.
The scene where Mrs. Doubtfire has icing melting off her face wasn’t intentional. The set lights were so hot it melted the icing and Williams improvised the rest.
Blake Lively was one of the finalists for the role that ultimately went to Mara Wilson, but said that her final audition with Robin Williams went “horrible” due to her nerves. She was only 5 after all.
They went through hundreds of photographs of 1940s English women to inspire Mrs. Doubtfire’s look.
The makeup took 4.5 hours to apply every day.
Supposedly, Robin Williams went into a sex toy shop in full costume to test the look. It worked and he went unrecognized.
Robin Williams improvised so much that there were 4 edits of the film: PG, PG-13, R, and NC-17. Sadly, PG-13 was always the intention and won in the end. Gotta see that NC-17 version.
Director Chris Columbus used multiple cameras to capture the cast’s reactions to Robin Williams’ improvisation.
The character that became “Mrs. Doubtfire” was first performed by Robin Williams at a show with Andy Kaufman at Carnegie hall, when Williams pretended to be Kaufman’s grandmother.
In the scene where Pierce Brosnan chokes on a shrimp Robin Williams kept trying to get Brosnan to laugh by telling dirty jokes.
Chuck Jones of Looney Tunes and Merrie Melodies fame supervised the opening animation segment.
The studio wanted the characters to get back together in the end, causing screenwriter Randi Mayem Singer to leave the movie. When Chris Columbus read the new, happier ending in the revised script he realized it didn’t work and brought Singer back to fix it.
There was talk of a sequel as early as 2001 and in 2014 Chris Columbus and Robin Williams announced they were working on the project together. Sadly, it was cancelled after Williams’ passing just 4 months later.
There could be a musical in the future, but it remains in hiatus.