With production scheduled to begin early next year, 'John Carter of Mars' appears to be getting all of its ducks in a row. Samantha Morton, Polly Walker and Dominic West have joined the cast, according to THR. 'John Carter' centers on a Civil War veteran that dies and is mysteriously taken to Mars. There, he takes a prominent role in a battle of Humanoids and Aliens. The film is being adapted from the Edgar Rice Burroughs books, with Taylor Kitsch (Friday Night Lights, X-Men Origins: Wolverine) in the title role. Morton will play Sola, the Tars Tarkas (played by Willem Dafoe). Walker plays Sarkoja, an evil Thark, and West will play Sab Than, a prince that wants to rule Mars.