Andy Serkis created the voice for other-worldly character 'Lord of the Rings' when he saw his cat coughing on a hairball.
The 46-year-old actor admits used the sound of his pet cat coughing up a hairball as his inspiration for the creature's unusual vocal expressions.
He said: "When I first learned I would play the role. The first thing to do was to read Tolkien. We had a cat named Diz and I watched him. Gollum is named that for the way he sounds. It's an involuntary reaction to the guilt he feels about killing his cousin.
"I thought, 'How can I find a sound that feels physicalised?' When a cat coughs, the movement from the tailbone to the tip of the spine, that choking sound was perfect for where Gollum kept his pain. The sound lent itself to the physicality."
Serkis also claims he felt drawn to the role of Gollum because of the unusual nature of his character.
He told the Huffington Post website: "Gollum was so interesting to me because he's morally ambivalent and I love the notion of a quest that is to lose something. Not to gain, but to get rid of something."
He recently confirmed rumours about 'The Hobbit' movie, which will begin shooting this month.
He said: "It's going to happen. I think it's due to start shooting in May. It's going to be exciting, especially working with new director Guillermo Del Toro, who's fantastic."