"This song changed my life," he said.
"I can only hope that now it might help, in some small way, to change the lives of our First Nations peoples for the better."
The Uluru Dialogue - the organisation dedicated to advancing the Uluru Statement - is launching a new film, You're the Voice, which pairs Farnham's anthemic song with transformative moments in Australian history.
Megan Davis, one of the Uluru Dialogue co-chairs, is hoping the video, coupled with Farnham's perfect soundtrack, will rally Australians behind the referendum, which will be held on October 14.
"I think for most Australians, this will be the defining song of the campaign," Professor Davis told AAP.
"You don't get anything bigger than John Farnham. He's Australian rock royalty and you don't get anything bigger than this song, which is the unofficial anthem of the nation.
"It is a huge deal. We're really proud."
The film, which is being launched on Sunday, is a direct call to action to remind Australians they have a chance to change history by voting yes.
The film follows a family through the years as they witness key moments play out on their TV screen; the 1967 referendum to count Aboriginal people in the Census, the Mabo decision, America's Cup, the Uluru handback, Cathy Freeman's gold medal, John Howard's 1996 gun reform, the 2008 apology and the marriage equality plebiscite.
"This isn't just the hard-headed constitutional reform that will change our people's lives, it's the heart as well, that's what this song speaks to," Prof Davis said.
"It speaks to the agency of people in a community working together to make a difference.
"It's been quite tough for our mob with the hate and the racism but the majority of Australians are forward-looking and this country actually is 'not gonna sit in silence' and 'we're not gonna live in fear'.
"We're going to step it up and walk together like we did in 1967 to make this change."
Just over a year ago, Farnham had major surgery to remove a cancerous tumour from his mouth.
He's been given the all-clear and in July a documentary about his life, Finding the Voice, was released.
And Farnsy isn't the only rock legend lending his star power and voice to the 'yes' campaign.
Singer-songwriter Paul Kelly wrote and released an original song, If Not Now.
"Music has the power to speak to people's lives," Prof Davis said.
"I was in primary school when You're the Voice was released and, as a young girl, instantaneously felt the power of its message about agency and walking together.
"History isn't just something we witness and observe, but something we ourselves can influence and now we all have a voice in what happens at this critical moment, and we must use it."
Prof Davis, a constitutional law expert and one of the architects of the Uluru Statement, has faced many questions about the voice since the Uluru summit in 2017.
She's written countless stories, appeared before numerous committees and conducted hundreds of interviews.
"The number one question Aussies have asked me for six years is 'Have you thought of Johnny Farnham and You're the Voice?'," she said.
"I just hope Australians love it.
"It's really about a few moments in our history that made us feel happy as a nation.
"There are some moments in our history when difficult decisions were made, we were anxious, but it made our country a better and safer place and that's what this is about."
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