The footage was taken by actor Samuel West who said he had been waiting for a year to be able to post it.
The film recreated the political chamber at Leavesden Studios near Watford, and also stars Kristin Scott Thomas and Lily James.
West, aged 51, took to Twitter with the video and captioned it: “Been waiting to post this for a year. Joe Wright, director of Darkest Hour, leads 450 MPs in a warmup sing of ‘Hey Jude’ between takes. ‘Gary Oldman as Churchill makes an entrance at the end. Darkest Hour is released in the UK today. Hope you like it.”
As Oldman enters the room he is immediately noticed by the film extras, who stop to give him cheers and applause.
The actor recently won the Golden Globe for Best Actor in a Drama for his portrayal of Churchill and also received a Bafta nomination, with several critics tipping him as an Oscars frontrunner for Best Actor.
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