, 45, took two years off from performing following the devastating news.
Thankfully, Noah was given the all-clear the following year, and shortly after, the star penned the song Forever Now, about his brave boy.
The hitmaker took to Instagram on Friday to pay tribute to his "hero" Noah as he celebrated his eighth birthday.
Alongside a string of adorable snaps, he penned: "Today my hero turns 8! I’ve never met anyone as brave…I've never known anyone as kind or as good-hearted…"
He continued: "And I’ll never truly be able to express how proud I am, or how deep and profound Mommy’s and my love is for you. You’ve blessed our lives in every way."
The singer added: "We hope God blesses you on your special day. Happy Birthday, Noah B."
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Michael married Argentinian actress Luisana Lopilato in 2011, and the couple also share son Elias, five, and daughter Vida, three.
After taking a break from music, the entertainer returned to the stage for an emotional concert at Dublin’s Croke Park in 2019.
He said: "My first show back, I played Croke and I cried for like two hours afterwards.
"It was too emotional for me. I was too happy. Noah is great, thank God."