Benedict Cumberbatch will join Keira Knightley at the European premiere of their new film which marks the start of the BFI London Film Festival.
The Sherlock star plays c ode-breaking genius Alan Turing in The Imitation Game, 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 plays his fellow-code breaker and one-time fiancee Joan Clarke.
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an act of "gross indecency" - in 1952, which led to his chemical castration and also saw his security clearance being withdrawn for his post-war work at GCHQ.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.
The film's d irector Morten Tyldum will also be at the screening at the Odeon Leicester Square and there will be s imultaneous screenings of the film at cinemas across the UK.
Festival director Clare Stewart said: "Featuring extraordinary performances from the British talent in front of the camera and vividly directed by Morten Tyldum, The Imitation Game does cinematic justice to Alan Turing's vision, determination and personal story as well as his enduring impact on British history and contemporary life."
The 58th BFI London Film Festival, in partnership with American Express, runs from October 8 to 19, with B rad Pitt's new Second World War drama Fury bringing down the curtain on the final day.
The 50-year-old Oscar-winner - who plays a battle-hardened army sergeant in the film - will walk up the red carpet at the European premiere at the Odeon Leicester Square.
Set in 1945, Fury - which will be released nationwide on October 24 - also stars Shia LaBeouf, Logan Lerman, Michael Pena and Jon Bernthal as an American tank crew embarking on a deadly mission behind enemy lines.