The casting announcement follows Friday's big news that Elijah Wood will play Frodo Baggins in the upcoming J.R.R. Tolkien two-part adaptation.
McKellan will again play Gandalf, while Serkis will portray Gollum. Both characters are vital to the tale of The Hobbit in which Gandalf recruits Bilbo Baggins (Martin Freeman) to join a quest to reclaim a dragon's treasure, and Gollum possesses a powerful ring that comes to play a pivotal role in both The Hobbit and the Lord of the Rings trilogy.
Are you excited about the casting news?