'Sherlock' stars Benedict Cumberbatch and Martin Freeman.
The preview shows more of actress Evangeline Lilly as the elf Tauriel as well as Benedict Cumberbatch's voice work portraying the dragon Smaug.
'Sherlock' is scheduled to air its third season in the US in 2014.
Smaug of the 'Hobbit' films is glimpsed for the first time, albeit in the shadows, in a new trailer for the second film in the planned 'Hobbit' trilogy, 'The Hobbit: The Desolation of Smaug.'
'The Hobbit: An Unexpected Journey,' which will be released Dec. 14, has received some early reviews. What do critics have to say?