Ryan Reynolds and Samuel L Jackson , along with Gary Oldman were seen in 2016, filming inside the council chambers on May 27 and were there until May 29.
The film follows the story of the world's top bodyguard (Reynolds) who's new client, a hit man (Jackson), must testify at the International Court of Justice.
Using Harrow Council chambers as a filming location seems apt for such a story line.
At the time of filming more than 100 extras were on set, dressed in judicial costumes as well as some in what seemed to be special forces military costumes.
Being a large production, movie equipment vehicles and catering trucks took up two of Harrow Council's car parks.
They also used a large crane to shine lights into the council chambers while the scenes were filmed.
Meena Vibhakar, Hansa Hirani and Dipti Hirani were some of the few spectators around when the filming was being done.
Meena said : "It's all very exciting isnt it?
"I think this is good for Harrow, to have such big and famous names here will be good.
" I would've thought that with these famous actors being here that more people would be outside, but maybe they aren't all on their lunch break."
Those who missed out on seeing the filming over the 2016 weekend in Harrow will get the opportunity to see the Council chambers in all their glory on the big screen on August 18.
It is not the only time Hollywood has come to west London to shoot its big budget blockbusters.
The latest Transformers epic was filmed in Syon Park in Brentford last year.
West London has also been used for Avengers: Age of Ultron, Tinker Tailor Soldier Spy and Love Acutally.
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