Commenting underneath his post was his friends and former co-stars, with Lynne McGranger writing: "Hey friend, you got this. Let me know when you and Tahnee are about and free. Must do food."
Georgie Parker also penned: "Go mate, you’re amazing Johnny, lots of love."
"Kicking that sh** to the kerb like a friggin rockstar," Larry Emdur added.
Johnny's girlfriend Tahnee Sims also posted a photo of him and expressed how she is "forever proud" of him as he goes through his battle with cancer.
The actor and singer was originally diagnosed with brain cancer in 2017 and later revealed he was all-clear of the disease back in 2019.
But in an Instagram post in November last year, Johnny shared the devastating news that his cancer had returned.
“After an unexpected week of seizures and excruciating headaches it is with a heavy heart that i have to let you know i now have another huge battle ahead of me as my brain cancer has returned,” he wrote alongside a photo of himself and Tahnee.
He continued: “Though i will dig deep and beat this sh*t disease again #f*ckcancer”.
The 33-year-old has previously opened up about how tough it was to hear the diagnosis and later fight the disease.
“It's pretty heavy hitting from the get-go so it's not something that doesn't really sink in straight away. As soon as you hear the news it's like... sh*t,” he revealed in 2018.
“It's been pretty full on. But I think as you go on, you kind of find ways to deal with it a bit more and just develop coping mechanisms.”