Well, if you're going to have Frodo(Elijah Wood) show up, why not have old Bilbo Baggins, too? Ian Holm played the elder hobbit in The Lord of the Rings, but seeing as The Hobbit
Jackson confirmed via the film's Facebook page that Holm would be back as Bilbo, but didn't say in what capacity. It seems likely he'll be in the framing sequences along with Frodo, telling the tale of Bilbo's journey to defeat Smaug the dragon...
One comment that came up from the recent video blog was the Bilbo voice at the end—many of you assumed it was Sir Ian Holm. Whilst Ian will be returning as the older Bilbo Baggins in The Hobbit, that recording was actually Martin Freeman’s voice, taken from a script read through we recorded when the cast first arrived. I have to admit, I wasn’t sure who it was when I first heard it, either. Cheers, Peter J
The Hobbit will be divided into two parts, currently shooting in New Zealand. Part 1 will be released on December 19th 2012, with the second half due the following year.