Why Wilfred is the dog's...pyjamas

The premise? Following a botched suicide attempt, former lawyer Ryan (Elijah Wood) makes a new friend - his sexy next-door neighbour's mutt Wilfred. Except, while everybody else sees just a dog, Ryan sees – yep – an Australian bloke in a dog suit.

In the show, Wilfred's origins are something of a mystery. But as far as the real world goes, it began life as an award-winning short film, became an Australian TV series, and was picked up for an American version by Family Guy’s David Zuckerman, pulling in its big-name star along the way.

But while Wilfred's plot, cast and location have varied, its one on-screen constant has been co-creator and dog-suit owner Jason Gann.

A former children's theatre actor, Gann was inspired to create Wilfred after watching kids’ entertainers in animal costumes swearing and smoking backstage during breaks.

His performance as the canine who thinks dogs are people, too, squeezes everything out of that incongruous setup. The fact that he's the onlycharacter in the show with an Australian accent only makes it better.

As this unusual crossbreed – described by Zuckerman as "part labrador retriever, part Russell Crowe on a bender" – goes about his business (and, yes, that often is a euphemism) he finds himself abruptly overtaken by irresistible canine urges.

The sudden snap into seething rage as he streaks off in pursuit of a passing car: “I hate you!” The confusion and frustration as he chases a torch light: "Ryan, are you seeing this? This defies all logic! Why can't I catch it?"

Or just those moments of innocent doggy enthusiasm. You know, frolicking in the surf on a beach. Killing a pelican. Humping a teddy bear, while a fag hangs from the corner of his mouth. That sort of thing.

But there's a less innocent side to Wilfred, too. A dark, manipulative, tricksy side that sees him sabotaging Ryan as often as he helps him.

Which raises the big question: who or what is Wilfred? Is he part of Ryan's psyche? His guardian angel? The devil on his shoulder?

It won’t spoil anything if I tell you that those questions remain largely unanswered by last night's series finale.

Thankfully, a second run has been given the go-ahead, and if you didn't catch the first series this time around, don't worry - BBC3 is promising to show it again before the end of the year.

Now you know all about it, why not watch it with a friend (imaginary or otherwise)? That weird bloke in the living room would love it.