However, the former Home and Away star cast his health worries aside and put on an upbeat show as he attended his first red carpet event last night.
Attending a charity gala at The Star in Sydney alongside his dancer girlfriend Tahnee Sims, the brave 29-year-old smiled happily for the cameras.
Whilst Johnny looked dashing in a black tux, Tahnee opted for a glamorous plunging black dress.
Johnny’s first public appearance comes juts days after he spoke to Nova’s Fitzy and Wippaabout the terrifying moment he was rushed to emergency after doctors discovered the cancerous tumour.
'It's 8am in the morning and she [Tahnee] gets a call from the emergency department, saying "you need get down here immediately because he's got a brain tumour", so she was in absolute tears at the time,' Johnny said.
'And she had to drive down there and they said "look, we need to do an emergency operation." Because by this stage, I had slipped into a coma,' he added.
'She had to sign a form to give permission.'
There was also a chance he could have died during his operation.
"I spoke to the neurosurgeon that did the operation… he said to me look, you know, if you hadn’t come in when you did you would’ve died that night," Ruffo told the radio hosts.
"You would’ve had a brain aneurism and not woken up at all.”
Speaking about the size of the tumour, Ruffo revealed that his neurosurgeon said the tumour could have been growing for two to 10 years.
To get rid of the remaining 5% of the tumour, the actor and singer is currently going through radiotherapy
This article originally appeared on New Idea.