Andy Serkis has said he had to forget a lot of what he learnt from The Lord Of The Rings in the new Hobbit movie.
The actor returns as Gollum in The Hobbit: An Unexpected Journey, the first in Peter Jackson's three-part adaptation of the novel.
But his character is 60 years younger than he was the last time Andy played him in The Lord Of The Rings.
"I did have to forget almost everything from Lord Of The Rings, because in The Hobbit Gollum hasn't been through any of [the trials] yet," Andy told the Radio Times.
"He's less physically scarred in the sense that he hasn't been tortured by Sauron, and he's not come out of the Misty Mountains.
"He's been in this cave, on his own, going crazy - but with the comfort of his "Precious", the Ring, the thing that he loves the most. It's his fix."
"When I was having my face cast [for prosthetic ears], I was told that the dimensions of Ian's and my face are almost identical, which they thought was a good omen," the Sherlock star said.
"I think he's got a tiny bit of a wider bridge of the nose. But all our measurements are kind of the same."