Jimmy Barnes, Tina Arena, Human Nature, Keith Urban and Jessica Mauboy are among the names to appear at the gig at Melbourne's Rod Laver Arena on September 20.
Farnham hoped the night would be about enjoying the music and having a laugh, while also raising funds for Head and Neck Cancer Australia, which supported him during his own battle in recent years.
"I've been incredibly lucky to spend my life doing what I love, and even luckier to have Australians embrace my music the way they have," he said.
"This night isn't about me — it's about giving something back and supporting a cause that means a great deal to me."
Farnham retired from public life after undergoing a 12-hour operation to remove a cancerous tumour from his mouth in 2022.
He has since been received formal confirmation from his medical team that he was all clear of cancer.
More than 120 artists will take to the stage during the one-night performance, including Celine Dion, Hugh Jackman and Richard Marx.
Dion and Jackman will perform remotely for a spectacular celebration.
"John Farnham is truly one of the great voices of the world. I have such beautiful memories of the time we shared on stage together — his generosity, his humour, and that incredible voice that fills your heart the moment you hear it," Dion said.
"It's such an honour and a privilege for me to be included to celebrate the extraordinary legacy John has given to music. He's an iconic artist, and he's also a deeply special human being. I know his songs will continue to live in people's hearts for generations to come."
Promoter Tony Cochrane told Nine's Today Show the concert was a way to thank Farnham for his lasting contribution to the music industry.
However, it was no easy task getting the show off the ground, he added.
"We had the unique problem that John wasn't so keen for it, (he) didn't think he deserved the attention," Mr Cochrane said.
"It took a lot of work to get him over the line and one of the key things is part of the proceeds of this show is to raise money for Head and Neck Cancer Australia."
Victoria's Minister for Sport and Major Events Steve Dimopoulos said the show will provide a big boost for the state's entertainment economy.
''This is going to be an unforgettable night, with stars from around the world paying tribute to an Australian living legend," he said.
Tickets go on sale at 10am on on Tuesday June 2 via Ticketek Australia.
11°C