Like many of the world's great discoveries - gravity, penicillin, Post-it Notes - Mark Seymour credits his pairing with fellow Aussie rocker James Reyne as "an accident".
The former frontmen of 80s chart stalwarts Hunters & Collectors and Australian Crawl respectively were both releasing solo albums when it was suggested they tour together. It made sense economically to combine touring costs and the double bill held huge punter appeal in their home country.
"We had 15 shows booked and it worked so well we ended up doing about 90 shows," Reyne says.
They've been touring regularly together ever since. Their joint star power allowing them to go places most acts can't financially make work.
"There's such big distances in Australia. The further inland you go, not many people go to those areas because of the pure economics of it," Reyne explains. "When we combined forces it really worked, especially going to those areas that people haven't gone to for years and years and years."
Now, it's bringing them across the ditch to play the Summer Concert Tour, the travelling mini-festival that specialises in relaxed vibes and legacy artists, that's being headlined by Supertramp's Roger Hodgson.
So the big question is how does their set work? Both their former bands have more than their fair share of heavy hitters.
"We do solo sets, essentially acoustic, then we introduce each other and combine," Seymour explains.
"We start really sparse with a simple acoustic presentation that builds to this big thing. We knocked this format together for convenience and then gradually realised that it works for the audience. It builds dramatically and musically," Reyne says. "During the combined thing we've got five to six people on stage. As we keep doing it we find the end set keeps getting longer and longer.
"It's fun doing our individual ones but it seems to be a little bit more fun when we're together."
With such a cracking catalogue of hits between them, Throw Your Arms Around Me, Holy Grail and Say Goodbye from Seymour's Hunters and Collectors and Boys Light Up, Beautiful People and Reckless from Reyne's Australian Crawl, how have they worked out what to play?
"It just sort of organically happened," says Seymour. Reyne goes into a little more detail.
"There are certain songs that we know people are going to want to hear. There are some obvious choices. Sometimes I'll have a favourite of Mark's and say, 'Can we try that one?' and we give it a run."
"He likes songs of mine that I don't," Seymour says. "I really like Boys Light Up and he really doesn't."
"But we've worked it out, we've got a fantastic arrangement that I love playing," Reyne says. "Mark's managed to reinvent Boys Light Up for me."
The late 80s/early 90s were a golden age for Australian rock music. Bands honed their craft in front of rowdy pub audiences, before looking further afield to take on the world. Many songs of that era are now considered rock classics. But how do these guys look back on those times?
Reyne laughs and answers quickly, "I tend not to", while Seymour is more reflective.
"As I get older there are certain defining moments that come to me in the dark hours... It feels as though it was over in a flash. I have vivid memories of playing at venues around Auckland, from the very first time we came here. There was this feeling of incredible freshness. It was exotic and strange to be here and it felt very different from Australia. But there was this big slab of time where the gigs were just barmy, one after the other and everything just blurred."
"For that whole time…" Reyne says, before trailing off. "I'm sure I was there, I know I was there because it's recorded I was there. And it's not one of those silly things like 'if you remember the 60s you weren't really there...'"
"We're still here now, which probably means we were looking after ourselves," says Seymour.
"Looking after ourselves and being very good, running, swimming… ate our vegetables," Reyne jokes.
Did they ever think that the songs they were writing would endure and still draw crowds decades later?
"Nup," Reyne answers immediately. "I certainly didn't. Reckless took about as long to write as it takes to play live. I didn't think it was any good. I didn't play it to anyone for years. To me, it was that weird song I'd written that one day I'd get to it and change the words.
"Often the song you think, 'what a piece of crap', people are going 'oh, Reckless!' 30 years later. I thought Reckless was silly. It didn't make any sense. It doesn't mean anything."
For his part, Reyne says he's now happy to throw his arms around his classic hits.
"There are these songs that have endured and resonate with people and you become very respectful of that," he says. "When people ask, 'do you mind playing your old stuff?', I say, 'it's not all of it, I play a few songs'. But they're there because they're good songs and you get to a point where you have to respect that. They exist in a world outside of you. So carrying that around is a pretty great thing to be able to do."
Who: James Reyne and Mark Seymour
What: Frontmen for Australian Crawl and Hunters & Collectors
When: Playing the Summer Concert Tour in Queenstown this Saturday followed by Taupo and Whitianga next Saturday and Sunday.