Benedict Cumberbatch has revealed that voicing Smaug the dragon was a testing experience in the latest Hobbit film.
The Star Trek Into Darkness actor, who lends his voice to the fire-breathing creature and the Necromancer in Peter Jackson's The Hobbit: The Desolation Of Smaug, admitted it took time to get Smaug's voice right.
"It was difficult. I was trying to articulate certain things which are impossible, because I'm a mammal trying to be a reptile," he said.
"One of them was the articulation of the neck, so that meant that everything got very strained in the voice, so it took me a while to make it deeper. It had to sound like he had the growl of an atomic explosion. It was great fun."
Benedict worked with a dialect coach to perfect his performance.
"It had to build that bridge between animal and human, something guttural, deep and rasped, kind of dry as well because of all the fire breathing," he continued, adding: "I don't think Smaug's cleaned his teeth in a while. He's got goat and dwarf breath."
The 37-year-old had to learn about doing motion capture as both characters too.
"I'd never worked with motion capture before, but I wanted to. I know I'm not Andy Serkis doing amazing, pioneering and masterful work as Gollum. I'm going to be mucking around as a serpent, and wriggling around on the floor trying to articulate things I can't do," he revealed.
Benedict added: "Smaug is the ultimate symbol of the corruption of power. He's a sleepy serpent on top of his pile of gold. It brings him nothing but a damp, dank retirement, no joy or humour. He's vainglorious and proud of his own power and wealth, but it has essentially ruined him."
:: The Hobbit: The Desolation Of Smaug is in cinemas now.