After reporting today that Luke Evans will play Bard in the Peter Jackson-directed The Hobbit and wondering who'll voice the dragon Smaug, Deadline can now tell you that it will be Benedict Cumberbatch. He'll portray Smaug via motion capture. He is already on the picture, providing the voice of the character Necromancer. This comes as Cumberbatch is getting buzz for his supporting performances in the Steven Spielberg-directed War Horse. And Tinker Tailor Soldier Spy, in which he stars opposite Gary Oldman, Tom Hardy and Colin Firth. After drawing raves for his performance in Danny Boyle's stage production of Frankenstein, Cumberbatch was just set to star in the five-part miniseries Parade’s End. Cumberbatch continues his role as Sherlock Holmes on the BBC/PBS series, which just won the BAFTA for Best Drama. He is represented by UTA and Conway Van Gelder.

Отсюда

Вторая роль - это Некромант в Лехолесье, т.е. одно из воплощений Саурона.
What's really interesting about the reporting done by Mike Fleming today is that he suggests Cumberbatch will also play the Necromancer, a somewhat minor character in "The Hobbit" who plays a fairly major role in the overall saga of Middle-Earth

Источник

О том, что роль Барда Лучника досталась Люку Эвансу уже написали и тут

Надеюсь Смог у Бена не будет так же слюни пускать