STORY: Peter Jackson, Ian McKellen Defend Making 'The Hobbit' a Trilogy

"Martin was the only person that we wanted for that role, and that was really before we met Martin," the director told reporters in New York. "We knew him from [the BBC's] The Office and Hitchhiker’s Guide [to the Galaxy], and we just felt he had qualities that would be perfect for Bilbo. The stuffy, repressed English quality. He’s a dramatic actor, he’s not a comedian, but he has a talent for comedy."

Persuading Freeman, who had never read J.R.R. Tolkien's Lord of the Rings books but enjoyed Jackson's film adaptations, to join The Hobbit was a relatively easy process. But delays on the project, thanks to MGM's bankruptcy, meant that they had no formal offer to present, and by the time Jackson could give him a contract, he had signed on for Sherlock.

Film Review: 'The Hobbit: An Unexpected Journey'

"We were in trouble. I was really panicking," Jackson said, adding that while he looked for other actors, no one matched up to Freeman. "I was having sleepless nights. We were probably six weeks away from the beginning of the shoot, and we hadn’t settled on anyone else, and I was torturing myself by watching Sherlock on an iPad at 4 o’clock in the morning."

But this is a man who has created an entire miniature universe in New Zealand -- and Jackson decided to make a major concession: After shooting with Freeman for four months, he let him go back to England for two months to film Sherlock.

As it turns out, it was a smart decision in more ways than one, Jackson said: He was able to edit the film and make adjustments in ways he would not have been able to do otherwise.

Freeman, meanwhile, had fun Wednesday tweaking the look of his small, furry-footed character.

"Bilbo went through a few faces. There were a couple of noses," he said. "They had the idea of having a more snub nose, and then they decided that my nose was weird enough. So it went from a more middle-aged rocker to being what Bilbo looks like now, which is a middle-aged rocker. So it was gradual; it wasn’t one minute you are you and then the next minute you are the character. It was incremental."