John Farnham's cancer battle has left him unable to sing.
While the 75-year-old Australian singer is now cancer-free after undergoing treatment including extensive surgery to remove a cancerous tumour from his mouth, he admitted that the procedure has affected his ability to fully open his mouth and sing.
Writing in his upcoming memoir, 'The Voice Inside', which has been previewed in the Sydney Morning Herald, John explained: "My facial disfigurement from the surgery means I can't open my mouth wide enough for a strip of spaghetti, let alone to sing.
"I can't get the movement to make the sounds I want to make, that's where the vibrations and my voice come from. It's a very disconcerting thing. And trying hurts."
However, he is hopeful that he will be able to sing again in the future.
He wrote: "I was given a gift and to be able to get out there and affect people in some way was special, I would like to continue doing that. Though I am not putting all my hopes into it, we'll see."
John also revealed that he believes his devastating oral cancer was caused by his previous smoking habit.
He said: "Cancer doesn't discriminate, but as soon as I was told the results, I couldn't help thinking it was my own fault, I smoked very heavily all my life."
Meanwhile, speaking previously about his book, John said: "I don't enjoy talking about myself, I really don't.
"Don't get me wrong, I'm an egomaniac, but dredging up the past is just not something I've ever really enjoyed.
"I'll try and share as much as I can, but that's not easy because I've never really been that open. I guess there are reasons for that. Reasons for my reluctance."
