The star, who died in 2014, was truly one of the greatest comic actors of all time, and that talent was on fine display in the 1993 movie.
In the first screen tests, he already has the character down to perfection.
As he meets his then-tiny co-star Mara Wilson, it’s clear that bosses had a great movie on their hands.
Watch above.
Mrs Doubtfire, which also starred Sally Field and Pierce Brosnan, was a huge success and amassed a hefty $ 441.3 million at the box office.
It won an Academy Award for Best Makeup plus Golden Globe gongs for Best Picture (Musical/Comedy) and Best Actor (Musical/Comedy).
It is widely considered to be one of the best family movies of all time, as well as one of Williams’ finest.
The star sadly committed suicide in August 2014, with his wife attributing his death to his struggle with Lewy body dementia.
He won an Academy Award in 1997 for Good Will Hunting, and his other famous roles oncluded The World According to Garp, One Hour Photo, Jumanji, The Birdcage and Dead Poets Society.
He also, of course, voiced the Genie in 1992’s Aladdin.