The 51-year-old director has been criticised for expanding the 'Hobbit' saga beyond two feature films, but Jackson said that the decision was inspired directly by author JRR Tolkien, reported Digital Spy online.
"A lot of the embellishment, almost all comes from Tolkien because he wrote a lot of notes for an expanded version that he was going to revise after 'The Lord of the Rings'. There were elements looking back at 'The Hobbit' that he wished he'd included," Jackson said.
"So he did have a lot of notes for what he was going to revise but he never got that book done. Those notes were published after his death at the end of 'Return of the King', so we were able to access a lot of that. All of the expanding and embellishment was based on the ideas Tolkien was exploring," he added.
Jackson also said that his primary goal with the 'Hobbit' series was to please Tolkien's most loyal fans. "I'm a JRR Tolkien fan and this is the Hobbit movie I'd love to see, but then you get to the point when you realise it's not all about you.
So you have to hand the movie over to the world and it's great that people have responded the way they have," he said. "The Hobbit: An Unexpected Journey" ill hit theatres on December 13 in the UK, and December 14 in the US.