Andy Serkis says that the design process of Smaug is a safely guarded secret.
Benedict Cumberbatch is set to voice the character of Smaug in Peter Jackson's The Hobbit and Serkis believes that it's going to be 'extraordinary'.
Speaking to MTV the actor said: "I can't give any secrets away, none of those trade secrets. I can't say that because actually it's still under wraps.
"It's still a very secret character that is very closely safeguarded, and it's still in the design process.
"With an actor like Benedict Cumberbatch playing him, it will be extraordinary."
Serkis will be back as Gollum for the two movies and he is also to direct the second unit.
The British actor is currently filming The Hobbit down in New Zealand alongside Martin Freeman, Ian McKellan and Richard Armitage.
The Hobbit: An Unexpected Journey is released 14th December.