Townsend, 37, has starred in the movies "Queen of the Damned" and "The League of Extraordinary Gentleman," and directed the film "Battle in Seattle." He is also the longtime partner of actress Charlize Theron.
Townsend was to play Fandral in Kenneth Branagh's big-screen adaptation of the "Thor" comic books, but he has been replaced by newcomer Joshua Dallas, The Hollywood Reporter said.
Starring Chris Hemsworth, Natalie Portman, Anthony Hopkins, Renee Russo and Tom Hiddleston, the picture is scheduled to begin this week.
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