Jess sends in this quote from the Australian Empire magazine:
‘Destined to be even more incident-packed than The Two Towers, The Return of the King will see Frodo and Sam battle the giant CGI spider Shelob and Aragorn travel the Paths of the Dead in an attempt to forge an army capable of vanquishing Sauron’s hordes. And as Andy Serkis reveals, the third film will provide audiences with a chance to see how Smeagol became Gollum.

“You see me on-screen transformed into Gollum once he kills his best mate Deagol,” enthuses the actor. “You see this whole descent into madness.”‘