Benedict Cumberbatch voices Smaug in Peter Jackson’s The Hobbit films.
Smaug is the dragon who occupies the Lonely Mountain and guards the treasure of the dwarven kingdom of Erebor. Cumberbatch provided the voice and performance for the character in The Desolation of Smaug and The Battle of the Five Armies, while digital artists created the final dragon on screen.
Cumberbatch also supplied the voice and motion-capture performance for the Necromancer, a separate character later revealed to be Sauron. That dual role can cause confusion, but Smaug and the Necromancer are entirely different figures in Tolkien’s mythology.
Smaug’s story begins before the events of the films, when he attacks Erebor and drives the dwarves from their homeland. Bilbo eventually enters the mountain and speaks with him, helping set the events of the final two films in motion.