The cast of Walt Disney's "John Carter of Mars" is growing, and Samantha Morton, Dominic West and Polly Walker are the latest to join the big-screen adaptation of Edgar Rice Burroughs' series of books.

Taylor Kitsch, Lynn Collins and Willem Dafoe are already part of the crew. The film focuses on a Civil War veteran (Kitsch) who is mysteriously transported to Mars, where he encounters a bunch of four-armed, green creatures.

The Hollywood Reporter says Walker will play Sarkoja, a tyrant, while West is set to portray Sab Than, a prince who believes he's been chosen to rule Mars. Morton plays Sola, the daughter of Dafoe's character Tars Tarkas.

Andrew Stanton, the guy behind "Finding Nemo" and "WALL-E," is directing. Morton was recently seen in "Synecdoche, New York." West was last seen as a villain in "Punisher: War Zone," and Walker's recent credits include "Rome."

Interesting cast!