Andy Serkis is kept awake at night by the challenge of playing Gollum.

The 62-year-old actor will return as the character in the upcoming movie The Lord of the Rings: The Hunt for Gollum (which he is also directing) and insists that the demands of the motion-capture role are taking their toll on him.

Speaking to The Sunday Times newspaper, Andy said: "I've just lived with Gollum for such a long period.

"I'm a terrible sleeper. My mind is pretty active and it has been insane going back to the character I started playing 26 years ago, and so I'm waking up at night…

"Actually, I don't know if I'm asleep or awake, but I think, 'Am I directing you, Gollum? Or you me? Are we arguing?' My mind is… busy."

Andy's work in the field of motion capture has been widely acclaimed since he first played Gollum in Peter Jackson's The Lord of the Rings trilogy in the early 2000s - a part he initially thought would only consist of "three weeks of voiceover".

Reflecting on his breakthrough, the Planet of the Apes star said: "Things were building gradually, but it was such a sliding doors moment, ridiculous.

"However, the way Gollum was described to me was that it was three weeks of voiceover and I thought, that's not what I do. That changed when I met Peter.

"I immediately saw the artistry. It was a special moment, because I loved Charles Laughton in The Hunchback of Notre Dame. I love transforming and this technology allows me to do that. I love making it not like me."

Serkis has combined motion capture roles with using his own features for acting but insists that he isn't motivated about reminding people of the man behind the technology.

He explained: "You know what? I never really cared about that.

"Because this technology is so misunderstood. I used to be evangelical. I've talked for hours about how performance capture is acting and watched eyes glaze over, but life's too short. I calmed down. Now I just think, 'If you get it? Great.'

"Performances like Gollum are authored by an actor in the same way a prosthetics team engineered John Hurt in The Elephant Man. But, for some reason, a performance underneath a physical mask is more understandable to some than this, which is a digital mask."