Robin Williams did so much improv on the set of Mrs. Doubtfire that 2 million feet of film had to be shot to accommodate him.Based on the novel Madame Doubtfire, the 1993 movie stars Robin as a floundering voice actor called Daniel who gets divorced and loses custody of his children.

Daniel comes up with a harebrained scheme to see more of his little ones – go into drag as a Scottish nanny and get hired by his ex-wife Miranda (Sally Field).

To mark 30 years since the film’s release, its director Chris Columbus fondly told Business Insider he kept ‘four cameras’ running at all times to ‘keep up with’ Robin.

In fact, Robin was such a whirlwind of improvisation that Chris still has ‘972 boxes of footage’ from Mrs. Doubtfire – and hopes to use some of it in a documentary.

Fizzing inventiveness: Robin Williams did so much improv on the set of Mrs. Doubtfire that 2 million feet of film had to be shot to accommodate him

The way he was: Robin is pictured in 2013, one year before he tragically committed suicide at the age of 63 after decades struggling with bipolar disorder and addiction

Workaday: To mark 30 years since the film’s release, its director Chris Columbus (left) fondly remembered Robin in a new interview; the pair are pictured on the set of the picture

After decades struggling with bipolar disorder and addiction, Robin committed suicide in 2014 at the age of 63 by hanging himself with a belt.

However in his new interview marking the 30th anniversary of Mrs. Doubtfire, the director focused on the happier subject of Robin’s fizzing inventiveness onscreen.

‘Early on in the process, he went to me: “Hey boss, the way I like to work, if you’re up for it, is I’ll give you three or four scripted takes, and then let’s play,”‘ Chris recalled.

‘By saying that, what he meant was he wanted to improvise. And that’s exactly how we shot every scene. We would have exactly what was scripted, and then Robin would go off and it was something to behold.’

Chris spared a thought for the ‘poor script supervisor’ Margaret de Jesus. ‘Remember, this is the early 1990s, she wasn’t typing what he was saying. She was handwriting it and Robin would change every take.’

The filmmaker shared: ‘So Robin would go to a place where he couldn’t remember much of what he said. We would go to the script supervisor and ask her and sometimes she didn’t even get it all. Often, he would literally give us a completely different take than what we did doing the written takes.’

He reflected: ‘If it were today, we would never end. But back then, we were shooting film so once we were out of film in the camera, we would say to Robin: “We’re out of film.” That happened on several occasions.’

Said he: ‘It got to the point that I had to shoot the entire movie with four cameras to keep up with him. 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.’

Premise: Premise: Robin plays a man with a harebrained scheme to see more of his children – go into drag as a Scottish nanny and get hired by his ex-wife Miranda (Sally Field) (right)

Wow: In fact, Robin was such a whirlwind of improvisation that Chris still has ‘972 boxes of footage’ from Mrs. Doubtfire – and hopes to use some of it in a documentary

Chris noted that as regards Robin’s co-stars ‘Pierce Brosnan and Sally Field, it was quite difficult for them not to break character.’

Lifting the curtain back on Robin’s creative process, Chris let slip two particular scenes that were the result of improvisation.

‘The entire restaurant sequence was amazing. When Robin playing Mrs. Doubtfire loses his teeth in his drink, you can see the glee in Robin’s face, he’s almost smiling to himself that he came up with that,’ he said.

The scene unfolds as Miranda goes out to dinner with boyfriend Stu (Pierce Brosnan), the children and Daniel in disguise as Mrs. Doubtfire.

During a toast, the false Mrs. Doubtfire teeth slip out of Daniel’s mouth and into his wineglass, leaving the adults at the table mortified.

Whoops: Chris let slip two particular scenes that were the result of improvisation – one being the ‘restaurant sequence’ when Mrs. Doubtfire ‘loses his teeth in his drink’

Making it work: Without breaking character, he starts trying to fish the dentures out of the wine with a fork, joking feebly: ‘Carpe dentum, seize the teeth’

Without breaking character, he starts trying to fish the dentures out of the wine with a fork, joking feebly: ‘Carpe dentum, seize the teeth.’

‘And the second one that stands out is what I call the pie-in-the-face sequence. It’s when Mrs. Sellner (Anne Haney) comes to Daniel’s apartment and he’s going back and forth as Mrs. Doubtfire and Daniel,’ he went on.

‘When he’s in the bedroom putting on the Doubtfire costume, that probably was his hardest work on the film. Verbally and physically. He was physically spent after doing that. I think we did 18 takes on that sequence.’

Chris revealed that he hopes to go back into his massive stockpiles of footage from Mrs. Doubtfire to piece together a documentary about Robin’s process.

‘There are roughly 972 boxes of footage from Doubtfire – footage we used in the movie, outtakes, behind-the-scenes footage – in a warehouse somewhere and we would like to hire an editor to go in and look at all of that footage,’ he said.

‘We want to show Robin’s process. There is something special and magical about how he went about his work and I think it would be fun to delve into it.’