Australian music legend John Farnham has been diagnosed with cancer, his family has revealed in a shock statement.
The You're The Voice singer is undergoing surgery in a Victorian hospital to remove a cancerous growth.
The "shock" diagnosis has prompted a wave of well wishes from around the world.
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"I haven't spoke with him since his diagnosis but it was a big surprise for us as well for him," friend, Lindsay Field told 9News.
"He was here for lunch three weeks ago and it was lovely, there was no suspicion at that time of this.
"Anyone you love and care for, you have a concern for their well-being."
Molly Meldrum was among those wishing him the best in his operation and recovery.
"He has been a friend of mine for a very long time, and we have been through lots in that time," he told 9News.
"He is the voice, there is doubt about that and he will always be the voice.
Kiss founding member Paul Stanley also posted to social media in a show of support.
"John… You ARE the voice!!! We are all sending you our prayers, energy and light for a full recovery," Stanley tweeted.
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Earlier today, entertainment reporter Peter Ford told 3AW details about his specific illness remained unclear.
"We don't know too much about the type of cancer that he does have. We know there is a tumour involved, but we don't know where on his body that would be," he said.
Surgeons are confident they will be able to remove all the dangerous tissue.
"Cancer diagnosis is something that so many people face every single day, and countless others have walked this path before me," Farnham said in a statement.
"The one thing I know for sure is that we have the very best specialist healthcare professionals in Victoria, and we can all be grateful for that. I know I am."
The family has requested privacy during this time.
Farnham has been a mainstay of Australian entertainment since he was billed as teen idol "Johnny Farnham" in the late 1960s.
The 73-year-old's 1986 album Whispering Jack, featuring the single You're The Voice, remains the second-highest selling album in Australia, behind only Meat Loaf's Bat Out Of Hell (1977).
He has received 19 ARIA awards, and was named an Officer of the Order of Australia in 1996, and Australian of the Year in 1987.