Will Smith fights with a younger version of himself in the first trailer of Gemini Man.

The Ang Lee film sees Smith star as Henry Brogan, an elite assassin who is suddenly targeted and pursued by a mysterious young operative who can predict his every move.

It turns out the mysterious operative is a younger version of himself, with the two characters coming face to face in the trailer released by Paramount Pictures on Tuesday.

The younger version of Smith questions the identity of the ageing assassin, asking: “He knew every move of mine before I made it. I’d have him right there, take the shot, and he’d be gone, like a ghost.

“Who is he?”

Both versions of Smith look noticeably different due to anti-ageing CGI technology.

His co-stars Mary Elizabeth Winstead and Clive Owen also feature in the action-filled trailer for the upcoming sci-fi film, which is set to a distorted version of Alphaville’s 1984 song Forever Young.

Gemini Man is due to be released on October 11 2019.