"The Animus is a machine that allows somebody to revisit the lives of their ancestor's," Fassbender says of the device at the heart of the film's plot alongside footage of his character Callum Lynch being inserted into the machine.
"It is genetic time-travel," adds Cotillard who portrays Sophia Rikkin, the leading scientist of the Animus project. "The subjects enter the Animus and they take the place of one of their ancestors," she continues.
"It's a very cool experience, it's just a fantastic concept," continues Fassbender as his character is shown leaping into action donning hooded armor and hidden wrist blades as an Assassin in 15th Century Spain.
Much like the video game series the film is based on, Fassbender will be thrown into a centuries-old conflict between the Assassins and the villainous Templars as he learns how to become a skilled killer through the Animus.
Directed by Justin Kurzel and also starring Jeremy Irons, Assassin's Creed arrives in theaters Dec. 21.