Smith first joined the much-loved soap in 1987, before leaving in 1991. He then rejoined the cast in 1996 and left once more in 2009. Then he popped up for a brief stint in 2011. And now he's back again.

And, said the self-described "jobbing actor", he's still having a great time playing Australia's favourite bumbling character, Harold Bishop.

"I needed it again," Smith said of his return. "I've tackled so many things since I've retired – things that stretch me, mentally and physically, such as photography, fly fishing and travel – and I needed to go back to my comfort zone, back in front of a camera."

"I enjoyed it immensely, especially because Anne (Charleston, who plays Harold's late wife, Madge) was there. My last bit of Neighbours before I retired was without Anne and it just wasn't the same. It didn't feel right. We walked back onto the set and within one scene it was almost as if we hadn't missed a step. We always had this wonderful thing going with us, which is very common with married couples in front of camera. We sort of trusted one another. We knew what the other was going to do, and really, rehearsal was a token gesture.

This time around, Madge is back from the dead –sort of – and Harold is dealing with that and a life in the new Ramsay Street. Any more than that about the anniversary special to be screened later this month is top secret.

"I didn't know how they were going to do it," he said of the anniversary. "I said to [the producers], 'Look, this doesn't sound too good,' and then they told me what the story was and I applauded the cleverness of it. It was an idea by [fellow cast member] Jackie Woodburne. It was written just right. I came back once before, and it wasn't a happy experience. This time things couldn't be better. As far as the producer [Jason Herbison] is concerned, and everyone in the office, they understand the business of soap. In the writing team, they understand the business of soap."

So too, he says, do his younger castmates.

"Every now and again when you're on the set, you'll see a head poke around the corner, and they're just there watching," he said. "It puts me in mind of what I used to do when I was a youngster, and I'd be working on Her Majesty's stage, and we'd have all the big names from England because they were all imported in those days, and I would stand in the wings and watch them work and see how they did it."

And whether this is Smith's final Neighbours appearance or not ("I've learned never to say never," he adds), fans shouldn't expect him to be swapping over to Ten's other big production du jour, I'm a Celebrity Get Me Out Of Here!.

He already did that for the UK version in 2011 and isn't keen to join the reality world again.

"No," he said. "I have to say, in all honesty, I did that for money. Purely and simply for money. It was embarrassing."

Neighbours, weeknights, Eleven, 6.30pm