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"Mrs. Doubtfire" is widely regarded as one of the best movies in Robin Williams' career. It certainly shows off his comedic and dramatic range like no other.

As the hit movie celebrates its 25th anniversary this week, here are some interesting facts you might not know about the saga of kindly old nanny Euphegenia Doubtfire.

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1. The movie is actually based on a 1987 novel by British writer Anne Fine called "Alias Madame Doubtfire."

2. A then-five-year-old Blake Lively tried out for the role of the youngest Hillard child, Natalie. She didn't get the part, obviously, but it doesn't seem to have harmed her career.

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3. Because of Williams' penchant for improvisation and adult humor, there are multiple, significantly different cuts of the film that range from a PG-13 rating all the way to very, very R-rated.

4. It took over four hours to apply Williams' makeup each day. During filming, he could sometimes be seen walking the streets of San Francisco in full costume rather than remove it to run errands.

5. The address Daniel gives the delivery driver is the actual address of the San Francisco home used for exterior shots of the Hillard household. Fans have been leaving flowers and gifts on the steps of the house ever since.

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6. Legendary "Looney Tunes" animator Chuck Jones was tapped to create the cartoon Daniel voices during the opening scene. The full five-minute short is available as a bonus feature on the DVD release.

7. Fox pressured writer Randi Mayem to change the ending so that Daniel and Miranda remarried. Mayem left in protest, and both the studio and director Chris Columbus eventually agreed that the film worked better without the happier ending.

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8. Numerous scenes and even entire subplots were cut from the final film, including a conflict between Daniel and his nosy neighbor, Gloria, and a fight between Daniel and Miranda at a spelling bee.

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9. Actress Lisa Jakub was expelled from her Toronto school for taking time off to film the movie. Williams wrote a letter to the school asking them to reconsider, but failed to change their minds.

10. "Home Improvement" star Tim Allen was offered both the role of Daniel and Stu at different points, but turned down both parts.

11. After years of struggling with developing the screenplay, a "Mrs. Doubtfire" sequel was officially announced to be in development in 2014. Unfortunately, Williams' death in August 2014 brought an end to that project.

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12. "Mrs. Doubtfire" may find a second life as a stage musical. A Broadway adaptation has been in the works since 2015.