It all started with Angelina Jolie.
Well, that's not quite true - it started more than 40 years earlier with a $10 guitar in Te Aroha - but Angelina made him realise a Northland farmer armed only with a guitar could give a voice to children affected by war.
The result, a song Merv Pinny calls OB (Can you hear the children cry?), seems to have struck a global chord because as of this week it had been viewed just under 13 million times.
It has been watched in Europe, the Middle East and Latin America. It has spawned a subculture of gas-mask-wearing fans and prompted young people caught up in conflicts to send the singer heart-felt emails.
It's not Pinny's first foray into recording - in the 1990s he made the finals of the NZ Music Awards - but it is the first time he's released a song internationally and dipped his toes into social media. So how did a simple blues-rock song by a Northland farmer get so much attention?
Pinny, who now lives in the Bay of Islands, grew up in a musical family on a Waikato farm.
His older brothers played in a band and would leave their instruments set up in the lounge.
"They were working so when I got home from school I'd get in to their gear, the drums, the synthesizer, whatever they had."
He bought his first guitar for $10 and got his first break aged 14 when the bass player in his brothers' band fell ill and had to be replaced at short notice.
The three siblings formed the Pinny Brothers Band and played the clubs around Te Aroha; a later band, Jailbreak, played the circuit in Hamilton. After gigs he'd still have to get up before dawn to milk the cows.
Pinny's next band, Destiny, brought his greatest success. In the mid-90s he was nominated in the best solo artist category of the NZ Music Awards.
A single, also called Destiny, won the rock single of the year title in the Waikato Music Awards.
Destiny was about finding himself and his path in life, but it wasn't to be in music. Not then anyway. A serious motorbike accident landed him in a hospital spinal unit, unable to walk properly for two years. His life, and his music, went on hold.
Pinny eventually returned to farming and writing songs. After a divorce he moved, reluctantly at first, to Northland - it was the only place he could afford to start again when he had to sell his Waikato farm - but then went from strength to strength.
Within a few decades Pinny had become Northland's biggest dairy farmer. At his peak Pinny and his second wife, Cara, owned 15,000 cattle, employed 65 staff and produced 20 million litres of milk a year.
Earlier this year they sold their remaining farms to the uber-wealthy Spencer family and Pinny, 56, was able to devote his new-found free time to music.
The sale went through just before milk prices dropped. It's no wonder his mates call him Tinny Pinny.
The theme for Pinny's comeback single was inspired by TV news items about the suffering of children caught up in wars, especially in Syria and Iraq, and the refugee crisis unfolding on Europe's borders. It distressed him and got him thinking.
"I was watching the refugees, the wars, the terrorism, and how desperate people are to leave their own countries. How desperate do things have to be before you jump on a plastic lilo and set off across the sea? How bad does it have to be before you do that?"
Then he saw an interview with actress Angelina Jolie - a UN special envoy for refugees - calling on governments, and ordinary people, to do more to help. And he realised there was something he could do.
OB (Can you hear the children cry?) is sung from the perspective of a fictional character called The Messenger.
"He's telling the story about what happened to him. He's a victim of war, he's got these images in his head and he's trying to get them out."
In the music video The Messenger wears a Russian gas mask which Pinny bought on eBay and had sent over from Australia.
In hindsight it was a stupid idea, Pinny says, because the mask piqued the interest of Customs officials wondering what he wanted it for. Months of web searches about war, terrorism and Isis may not have helped.
Eventually Pinny managed to persuade Customs he wanted the mask for a music video. It has since spawned a peculiar subculture in which fans wear gas masks in their Facebook profile photos.
Pinny recorded the song in a converted boat shed at his Purerua Peninsula property with the mixing done at Crank Studios in Perth. Only the drums were played by a professional musician.
He made the video himself - a painfully slow process because he had to teach himself by googling every step - then called on another Northlander, Bridget Thackwray from Mahinepua, to help him promote the song on social media.
"Facebook isn't my strong suit. She did a fantastic job, it all happened so fast."
One evening in July Thackwray told him to post a link to the video on his Facebook page as a test. Pinny didn't realise he was supposed to take it down again straight away.
Within an hour the video had been watched 1400 times so they decided to leave it and see what would happen. Pinny thought it might reach 2000 views.
In the meantime Thackwray had been tapping into her social media contacts in the UK and sharing the video with social media groups dedicated to the refugee crisis.
Pinny says the song really took off when Facebook groups at universities in Latin America started sharing it. With some groups counting more than 60,000 members it didn't take long to snowball. Even now, months later, viewer numbers spike any time war makes the news, and people Pinny has never met keep re-posting the song.
Earlier this week the video had been watched 12,950,000 times. By the time you read this it will almost certainly have passed 13million.
The sheer numbers, however, don't move Pinny like the emails he has received from people caught up in wars the Middle East.
"Some young people from these countries have told me, 'This is just like my life'. They've really jumped on it. They got excited that someone was writing songs and actually talking about it. I think a lot of them felt that nobody cared," he says.
The online interest has prompted radio stations in the US to take notice. It was first picked up by a radio station in Seattle. In recent weeks it has made the airwaves in LA, Houston and Miami.
It's a far cry from Destiny, which was released only in New Zealand in the pre-internet days when musicians depended on the whim of record companies to be heard.
Right now Pinny is working on two follow-up numbers. He hopes to release the second before Christmas but it's a time-consuming process because he wants to do as much of it as he can himself.
To speed things up he's upskilling himself with music production and film-making courses in Auckland and Australia.
OB (Can you hear the children cry?) is being sold through the usual online outlets such as iTunes, Spotify and Google music.
All proceeds will go to a charity for children affected by war, with World Vision's Children in Crisis a likely candidate.
A song isn't going to silence any guns on its own but at least he feels like he's doing something.
"Maybe it'll help, but stopping the wars would be the best thing that could happen for those kids."
- Merv Pinny and the Bootleg Band play regularly at McMorrisseys in Whangarei. Coming Far North gigs include Soundgarden Festival in North Hokianga on January 29 and the Ocean and Orchard Festival in Kerikeri on February 25.