According to The Hollywood Reporter, Dafoe is set to play Tars Tarkas. Tarkas is a great Martian warrior and leader, a member of a fairly brutal Martian society called the Tharks-- think Spartans, only with even less of a sense of humor.

Tarkas and the titular John Carter are at odds initially, but over the course of their adventure they come to admire and respect one another. Eventually Tarkas reveals his tragic background (one I won't spoil for you -- just read the book), and proves that he's a kind rarity among his brutal people. Thanks to Carter, the Martian eventually becomes ruler of the Tharks. Dafoe will be able to do wonders with the role, as it's just the sort of grim, sympathetic figure he really specializes in.

The film will begin shooting in early 2010, with Utah standing in for Mars. "John Carter of Mars" is set to arrive in theaters in 2012. There's still a lot of pre-production geek outs ahead of us, you've been warned!

Are you looking forward to "John Carter of Mars" as much as we are? What do you think of the addition of Willem Dafoe? Who else would you like to see cast as a Martian?