The main characters of the film, to be played by Dane DeHaan and Cara Delavingne, are... "Valerian and Laureline, a pair of spatio-temporal agents who help defend an utopian 28th century Earth and its neighboring planets from bad guys, with the pair's adventures rooted in space opera and time travel themes."
Deadline reported yesterday that Ethan Hawke, no stranger to sci-fi and time travel, one of the themes in Besson's adaptation of the French graphic novel series by Pierre Christian and Jean-Claude Mézières.
Today The Wrap is reporting that John Goodman is also joining the cast and will be lending his voice to one of the alien characters.