Almost a week ago, and without any fanfare, Nikki Finke listed John Carter of Mars as one of Michael Chabon’s screenwriting credits; this was then followed up by a Chabon fansite, The Amazing Website of Kavalier and Clay, and they got the author himself confirm:
I’ve been hired to do some revisions to an already strong script by Andrew Stanton and Mark Andrews. I wrote my original screenplay The Martian Agent back in 1995 because I wished I could do Burroughs’s Barsoom. So this is pretty much a dream come true for me.
And for me. If you aren’t doing a little dance around your room right now, then I don’t think you’ll be at my next birthday party.