A new trailer released this week shows the present-day Smith as Henry Brogen, a brilliant but ageing assassin who finds himself being chased by a young clone who seems to pre-empt his every move.
The film is the latest movie in 2019 to use technology to make its star look younger, following Captain Marvel, which de-aged Samuel L Jackson so he could play MCU character Nick Fury in the Nineties. Martin Scorsese is using similar VFX on The Irishman to de-age Robert De Niro and Al Pacino.
See some of the reactions on social media, below:
Early reviews from critics have offered a highly positive reaction to the special effects in Gemini Man, with it being called "stunning" and "eye-popping".
Filmmaker Ang Lee also shot Gemini Man in 3D at 120 frames per second with 4k resolution, as he did with his previous film Billy Lynn's Long Halftime Walk.
However, critics were less keen on this method and complained that the footage was hyper-real and ended up looking like a video game.
Paramount will be releasing Gemini Man at normal frame rates as well as 3D. The film is released in cinemas on 11 October.
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