It’s one of the most memorable scenes in Robin Williams’ hit 1993 comedy “Mrs. Doubtfire.”

Dressed as an old English woman so he can spend more time with his kids, recent divorcee Daniel Hillard (played by Williams) is surprised to find court-appointed liaison Mrs. Sellner at his apartment for a check-in. He’s now forced to frantically change back and forth from Daniel to Mrs. Doubtfire while Mrs. Sellner is in his apartment — even putting his face in a cake at one point when his Doubtfire mask is destroyed.

Williams is at his comedic peak in this sequence, and it turns out that to pull off this greatness he shot the sequence over a dozen times.

“When he’s in the bedroom putting on the Doubtfire costume, that probably was his hardest work on the film,” director Chris Columbus told Business Insider during an interview celebrating the movie’s 30th anniversary. “Verbally and physically. He was physically spent after doing that. I think we did 18 takes on that sequence.”

It was all worth it. Not only did that sequence birth the famous cake face shot, but the movie itself became a box office hit and one of Williams’ most memorable roles.

Chris Columbus talking to Robin Williams dressed as Mrs Doubtfire

(L-R) Chris Columbus and Robin Williams on the set of “Mrs. Doubtfire.” 20th Century Fox

“He was in his prime at that point in his life and it was like divine inspiration,” Columbus said, thinking back on Williams’ work on the movie, which resulted in 2 million feet of film used to capture all of his improvisation.

“It got to the point that I had to shoot the entire movie with four cameras to keep up with him,” Columbus said. “None of us knew what he was going to say when he got going and so I wanted a camera on the other actors to get their reactions.”

Columbus said that there are over 900 boxes of footage from the movie currently sitting in storage that he’d like to one day make into a documentary.

“We want to show Robin’s process,” Columbus said about the potential documentary. “There is something special and magical about how he went about his work and I think it would be fun to delve into it.”