“Oh man, I’m a glorified tag-along this time around,” Elijah Wood jokes about his forthcoming return to the Lord of the Rings film franchise. And despite the playful sarcasm behind his American drawl, he’s actually not far off the mark.

On The Hobbit…

Wood, who turned 30 this year, made the leap from likeable child star to credible adult actor as Frodo Baggins in Peter Jackson’s fantasy trilogy (released 2001-2003). But the timing of the two prequels, The Hobbit: An Unexpected Journey and The Hobbit: There and Back Again (set for release in 3D in 2012 and 2013), predate his character’s existence.

In the original text by JRR Tolkien, Frodo is yet to be born, so how has Wood managed to wangle himself a part in the film adaptations? “I suppose you’ll have to wait and see,” he teases, speaking to RadioTimes.com from his home in California. “But Frodo obviously does not exist, so it will ultimately be a very small piece that will happen within the time frame of The Lord of the Rings and is woven into the context of The Hobbit.”

Ian Holm, who originally played Bilbo Baggins, is also reprising his role, but Martin Freeman (The Office, Sherlock) will take over in the lead role as his younger self. “He’s wonderful,” Wood says of Freeman. “I haven’t met him yet, but I was so excited to hear he was cast as Bilbo - he’s so perfect and I’m a fan of his work.”

Since The Lord of the Rings, Wood has gone on to further prove his acting credentials, starring in, among others, Eternal Sunshine of the Spotless Mind, Sin City and Green Street. And he is currently proving his boyish charm can be applied to the comedy genre in the hit TV series Wilfred (Tuesdays, 10:30pm on BBC3).

On Wilfred…

The show, a second season of which has just been commissioned, is based on an Australian short film and series of the same name, written by and starring comedian Jason Gann. Wood plays the part of Ryan, a washed-up former lawyer who lives next door to an attractive blonde, Jenna, and her dog, Wilfred (Gann). Everyone sees Wilfred as a normal dog, but Ryan - like the audience - sees a big Aussie bloke in a dog suit.

“I was immediately pleased that the original creator would be involved for the duration,” Wood says, “because oftentimes America has remade a number of English and Australian shows, and the quality and integrity is not always there.

“I’d never really read anything similar or seen anything like it on television. I just found it incredibly funny and multi-layered,” he adds.

After growing up with pet dogs, Wood also recognised the subtle dogisms that are crucial to the understated humour within the show. “One of the things I loved so much in the pilot, and it’s so simple, was him (Wilfred) walking into my living room and turning around three times before he sits down.”

Wilfred is produced by David Zuckerman (The Fresh Prince, Family Guy) and comparisons have been made with the 1950 film Harvey, starring James Stewart as a middle-aged man who befriends an invisible rabbit. It is a movie that also happens to be one of Wood’s favourites. “Oh, I love Harvey, I’ve seen it so many times. The notion of what psychologically is bringing about that imaginary friend, I find so interesting.”

Wilfred creator Gann also freely admits to being “baked” (high on marijuana) when he came up with the original idea for the show back in 2001, during a conversation with his friend (and later co-creator) Adam Zwar. The characters (including the dog) are regularly seen using a home-made bong in the show – an element that Wood feels is integral to the surrealism of Wilfred.

“What is happening and what is not happening is constantly in question and I love that. It is a bit bizarre, though, and that is certainly aided by copious amounts of marijuana.” Wood is quick to clarify at this point that he is talking about the characters’ rather than the actors’ drug use on set, to avoid any confusion.

It isn’t needed, but it shows how media savvy he has become in an already long acting career. He also laughs off the suggestion that he is wearing eyeliner in the show, or in any of his other roles – he’s charmed that RadioTimes.com was convinced of it.

The chemistry between the two leads is what makes Wilfred so watchable, and Wood credits the “shorthand” he developed with Gann for this, saying it often led to hilarity between takes. “I actually put on a part of the dog suit once, which freaked Jason out. I put on the head and took a photo of myself with it. He thought it was hilarious but he’s been living that thing for years and years, so it’s sort of an intimate relationship he has with it.”

On TV, comedy and music…

So if Wood had a pet dog that could talk, like Wilfred, what would it tell us about him that no one else knows? Perhaps a guilty TV pleasure he has? “Er… I was a fan of The Biggest Loser for a while,” he says, through gritted teeth. “It’s actually very addictive,” he insists, getting excited when he hears there is also a British version.

He also enjoys the big HBO TV dramas, something he’d consider doing in the future. “I love Breaking Bad, Mad Men, and I’m a huge True Blood fan,” he says, admitting to recently catching up on The Wire in bulk sessions. “I’ll tend to start a marathon in the evenings and probably order in food - and I drink a lot of maté tea (a high-caffeine South American tea) so I can stay awake.”

His current comedy champions are Zach Galifianakis - “he just has a great sensibility to him” - and Louis CK - “I don’t know if you have him over there yet but his show, I think, is the best comedy show on at the moment in the States.” He also loves Flight of the Conchords, a programme that gained a huge cult following much as Wilfred is now developing.

“I’m a fan of British comedy as well,” he adds. “The League of Gentlemen is brilliant, Garth Marenghi’s Darkplace, and I’m a huge Chris Morris fan – any of his shows from The Day Today, Brass Eye to Blue Jam, I love.”

As well as being into comedy, Wood also runs his own music label, Simian Records, and takes a keen interest in new bands and artists. (In case you’re wondering, Metronomy, Luke Abbott, Kimbra, and Tom Waits are on his current playlist).

On his future projects…

Work on the scripts for the second series of Wilfred begins next month, with Wood getting a first look in November. He is also once again lending his voice to animated penguin Mumble in Happy Feet Two (released 2 December) and has several projects in the pipeline for next year.

As well as starring in The Hobbit, he is set to play a gay friend in anti-rom-com Celeste and Jesse Forever, voice Tron: Uprising, a TV animation series, for the US Disney channel, and appear in indie dark comedy Revenge for Jolly, opposite Bridesmaids’ Kristen Wiig.

For now, though, he will need to dig out his hobbit feet as he prepares to return to New Zealand to film The Lord of the Rings prequels (both parts are being made back-to-back) before the end of the year. And it’s a comeback he can’t wait for. “I jumped at the chance to go back. It’s largely the same crew and the same creative team involved in The Hobbit, so it’s like stepping back in time and having an amazing family reunion.”

And as if by chance, Wood still owns an original pair of hobbit feet, given to him by Peter Jackson at the end of the last film. “They’re in a box on a shelf somewhere,” he says. “They’re made of latex and I haven’t actually checked on them in quite some time. They may have rotted by now - I should probably go and see.”

Wilfred is on BBC3 tonight at 10.30pm