The 2-minute, 29-second clip premiered on YouTube Tuesday.
Smaug is the name of the giant, red, treasure-guarding dragon the heroes will encounter in the next "Hobbit" movie, which is due in theaters Dec. 13.
Benedict Cumberbatch, Freeman's co-star on the TV series "Sherlock," lends his voice to the fire-breathing monster.
"The film continues the adventure of the title character Bilbo Baggins as he journeys with the wizard Gandalf and 13 dwarves, led by Thorin Oakenshield, on an epic quest to reclaim the lost Dwarf Kingdom of Erebor," a synopsis said. "Having survived the beginning of their unexpected journey, the company continues east, encountering along the way the skin-changer Beorn and a swarm of giant spiders in the treacherous Mirkwood Forest. After escaping capture by the dangerous Woodland elves, the dwarves journey to Lake-town, and finally to the Lonely Mountain itself, where they must face the greatest danger of all -- a creature more terrifying than any before, which will test not only the depth of their courage but the limits of their friendship and the wisdom of the journey itself -- the Dragon Smaug."
The movie is the second installment in a planned trilogy based on J.R.R. Tolkien's novel "The Hobbit."