The two stars are set to play warring gods in the update of the cult 1981 film.
Neeson will play Zeus, according to the Hollywood Reporter, while Fiennes is in negotiations to take on the role of Hades, ruler of the underworld.
The film set will be a more cheerful get-together for Neeson and Fiennes, who last met at Richardson’s New York state funeral in March.
Mikkelson will play Draco, a fearless warrior, while the British Arterton will take on the part of Io, a love interest of the movie’s protagonist Perseus.
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