As announced by director Peter Jackson earlier this week, the trailer includes previously unseen content.
The release is in honour of Tolkien Week celebrations for the 75th anniversary of The Hobbit.
Martin Freeman stars as Bilbo Baggins in the adaptation, while Ian McKellen, Andy Serkis, Hugo Weaving, Elijah Wood and Cate Blanchett are among the Lord of the Rings cast members who will reprise their roles.
New additions to the cast include Richard Armitage as dwarf Thorin Oakenshield, Evangeline Lilly as elf Tauriel, and Benedict Cumberbatch as villainous dragon Smaug.
a trilogy of films will be produced, rather than two as was originally planned.
The Hobbit: An Unexpected Journey will be released on December 14.