Martin Freeman, Ian McKellen and Richard Armitage feature in the short trailer, which features new snippets of dialogue from Gandalf (McKellen) and Thorin (Armitage).
"The world is not in your books and maps," Gandalf tells Bilbo (Freeman), trying to persuade him to leave his comfortable home and embark on a dangerous quest.
This will be the first of three Hobbit instalments from director Peter Jackson, with Andy Serkis, Elijah Wood, Hugo Weaving, Cate Blanchett and Orlando Bloom all expected to reprise their Lord of the Rings roles.
It was recently confirmed that an extended edition of The Hobbit: An Unexpected Journey will be available on DVD and Blu-ray in 2013.
The Hobbit: An Unexpected Journey will be released on December 14.
Watch the film's full trailer below:
Photo gallery - The Hobbit: An Unexpected Journey: