Willem Dafoe goes to Mars July 16, 2009 Spider-Man’s Willem Dafoe joins John Carter of Mars. Willem Dafoe (Spider-Man) is set to star opposite Taylor Kitsch and Lynn Collins in fantasy epic John Carter of Mars. Directed by WALL•E helmer Andrew Stanton, Dafoe will play the role of Tars Tarkas, a fierce green Martian warrior, who’s unusual among his savage race for his ability to love. Tars develops an alliance with John Carter in the first film, which is based on “A Princess of Mars.” He fights battles alongside Carter through the entire series of Edgar Rice Burroughs books, so he will be hanging around for sequels. Stanton wrote the script with Mark Andrews.