The 30-year-old teamed back up with Lord of the Rings director Peter Jackson and co-stars including Orlando Bloom, Cate Blanchett, Andy Serkis and Ian McKellen to reprise his role as Frodo Baggins for the upcoming picture.
"The opportunity to go back to New Zealand to play that character again... it felt like a family reunion," he told E!.
"It felt like stepping back into time. I turned 19 in Hobbiton and I'm 30 now!"
Jackson, meanwhile, stated that he was pleased with how The Hobbit is progressing.
"It's going great," he said. "We're probably two-thirds of the way through shooting and I go back to New Zealand in about two weeks and we start another hundred days of shooting."
Ian Holm, Christopher Lee and Hugo Weaving are also due to reprise their Lord of the Rings roles for The Hobbit, while Martin Freeman, Evangeline Lilly, Richard Armitage, Stephen Fry, Benedict Cumberbatch, Sylvester McCoy, Bret McKenzie and James Nesbitt are amongst the newcomers.
The Hobbit: An Unexpected Journey is released in the UK and US on December 14. Part two There And Back Again will follow in 2013.
> The Hobbit: new picture of Martin Freeman as Bilbo Baggins released
> The Hobbit: Elijah Wood returns to the Shire in new on-set video
> The Hobbit artwork teases Bilbo Baggins in An Unexpected Journey
Watch the trailer for The Hobbit: An Unexpected Journey below: