The Lord of the Rings trilogy was a life-changing experience for many involved. None more so than for Andy Serkis, whose acting career was turned upside down by his portrayal of Gollum, a role which has propelled him from a minor actor to a major star - and the world's leading proponent of performance capture.
"It has been quite an extraordinary experience," he says. "If I hadn't met Peter and played Gollum then things would have been immeasurably different because, without question, they've both completely changed my career, and led me down a very different path.
"I would never have got into performance capture otherwise," he acknowledges. "It's entirely defined the last 10 years of my life, to the point where I now have my own film studio, The Imaginarium, where I'm developing my own projects using performance capture, which I believe is the future of film-making."
For the moment though, Serkis is happily doing what he does best - bringing Gollum back to life in The Hobbit: An Unexpected Journey.
However, despite his past performances in the Lord of the Rings trilogy, Serkis admits that reprising his role for The Hobbit was anything but child's play.
"I actually found it incredibly hard to find the emotional heart and soul of the character again," he says. "I think it's because in the 10 years since playing Gollum there have been thousands of spoof impressions of him, so when it came to the first day of filming I actually found myself doing an impersonation - a caricature - of him. It was very weird.
"Luckily, Peter spotted what was going on and suggested we play the 'Riddles in the Dark' scene, which is very long, out in its entirety, to get me back into character and ease Martin Freeman into the role of Bilbo Baggins. That was a very clever ploy and it worked.
"It was great to play that scene because, as a kid, The Hobbit was one of the first books I read and I vividly remember the 'Riddles in the Dark' passage, and always dreamed about doing it," he adds, smiling. "So, it meant a lot to finally play it, after all these years."
There was another dream-come-true moment for Serkis, during filming, which meant even more to him: when Jackson asked him to help direct.
"That was a huge surprise," he says. "I was only supposed to be going down for two weeks to reprise the role of Gollum but, just before we started shooting, I got an email from Peter saying he wanted me to direct the second unit. I was stunned.
"It was an incredible honour and I jumped at the chance," he enthuses. "Actually, in many ways, it was perfect timing because I was already planning to direct a couple of films that we were developing in our studio. But instead of my first film being a small, independent one, it ended up being the biggest second unit possible, shooting in 3D, for 200 days - the equivalent of five independent movies. It was crazy."