A touching letter written by Crocodile Hunter Steve Irwin to his parents has been uncovered, 10 years after he died.

The legendary conservationist penned the memo to Lyn and Bob Irwin when he was just 32 years old.

View photos The Crocodile Hunter died on September 4, 2006 after being pierced in the chest by a stingray while filming a documentary underwater. Photo: AAP More

Steve's father Bob recently discovered the unopened letter after it fell from a book while he was researching information for his memoir, The Last Crocodile Hunter: A Father and Son Legacy.

The heart-breaking piece outlined Steve's gratitude to his upbringing and revealed a man who had just started to find joy and understand his purpose in life.

“Probably one of the most unfortunate things in a bloke’s life is that it takes over 30 years to realise how essential you have been to build my character, my ethics and, most importantly, my HAPPINESS,” Steve wrote.

View photos Steve Irwin penned the memo to Lyn and Bob Irwin when he was just 32 years old. Photo: AAP More

“At 32, I am finally starting to figure it out. In good times and in bad, you were there.

"Your strength and endurance to raise me will not go unrewarded. My love for you is my strength!

“For the rest of my life I will reflect on the unbelievably GREAT times we’ve shared and will continue to share.

"You’re my best friends!”

View photos This is the cover sleeve for Bob Irwin's memoir The Last Crocodile Hunter: A Father and Son Legacy. Photo: AAP More

Bob has told his story to Amanda French, who co-authored his memoir, over a 20,000 kilometre road trip.

"Working on this book I have been constantly reminded of Steve's boundless energy, infectious humour and unrestrained passion for wildlife," he said.

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