Although he joined the film a while ago, we've only just learned who Willem Dafoe will be playing in the Justice League movie, which arrives on November 17, 2017.
He'll star as Nuidis Vulko, an Atlantean who is also the chief scientific advisor of Atlantis, so we'll probably see him assisting Aquaman throughout the film.
This casting seems to strongly indicate that Dafoe will also be appearing in James Wan's Aquaman movie, which goes into production soon ahead of a July 27, 2018 release date.
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