Robert Irwin breaks down after receiving a special 19th birthday message from Steve Irwin

September marked 16 years since beloved Australian wildlife expert Steve Irwin passed away.

But the Crocodile Hunter made sure to leave behind a special birthday message for his son, Robert Irwin.

While celebrating his 19th birthday at Australia Zoo with a full crowd, the conservationist was brought to tears after he was played an emotional birthday video tribute from his late father.

The heartwarming footage included Steve talking about his son and how he hoped he would become the next crocodile hunter.

The video goes on to show clips of Robert at the zoo at different times in his life continuing his father’s mission.

Robert and his sister Bindi, who were just two and eight years old respectively when their famous father died, have worked tirelessly alongside their mother Terri to honour their father's wildlife warrior legacy.

Steve Irwin died on September 4, 2006, after being struck by a deadly stingray barb while filming for one of his many TV shows off Port Douglas in North Queensland, and left a family, a nation, and the world in shock. He was 44.