Benedict Cumberbatch and Keira Knightley have opened this year's London Film Festival with The Imitation Game, drawing crowds to London's rainy Leicester Square for the film about British code-cracking genius Alan Turing.
Benedict, 38, plays Turing in the film, which is set at Bletchley Park, where teams worked around the clock for years to unscramble messages encrypted by the Enigma machines used by German forces.
Keira, 29, plays his fellow code-breaker and one-time fiancee Joan Clarke, and both were on the red carpet before the film's screening at Odeon Leicester Square in London, where the festival kicked off.
Turing, regarded as one of the fathers of computing, was given a posthumous royal pardon in December for his conviction for homosexuality - or an act of "gross indecency" - in 1952, which led to his chemical castration and also saw his security clearance being withdrawn for his post-war work at GCHQ. He went on to commit suicide in 1954.
It has already been suggested that Sherlock star Benedict could get an Oscar nod for his performance, to which he said: "If it gets people to see the film, frankly that's all I care about. It's very early on and there are a number of other extraordinary performances and films that we haven't seen yet and that are being talked about.
"If it creates an interest for people to see the film then that's fantastic because it makes our jobs as storytellers much easier, and more importantly for me, having had some experience with this extraordinary man I really want his story to be known as broadly as possible."
His co-star Charles Dance, who plays Turing's boss Commander Denniston, said of Benedict: "If he doesn't win an award, or a big gong, or preferably a statue of a little gold man, I will be astonished."
Keira said that she felt proud to see The Imitation Game launching the festival: "All of the cast are London born and it's a very British film about a very important part of British history so it feels lovely to be here."
The pair were joined at the event by The Imitation Game's stars Allen Leech, Mark Strong and Matthew Beard, and director Morten Tyldum.
The 58th BFI London Film Festival, in partnership with American Express, runs from October 8 to 19, with Brad Pitt's new Second World War drama Fury bringing down the curtain on the final day.
The Imitation Game is released in cinemas on November 14.