Go in peace Steve, We'll miss ya!
Mr Irwin, 44, was killed by a stingray barb to the chest while he was filming an underwater documentary in Queensland's Great Barrier Reef. Paramedics from the nearby city of Cairns rushed to treat him at the scene but were unable to save him.
Mr Irwin was known for his television show The Crocodile Hunter and his work with native Australian wildlife. Police in Queensland confirmed the naturalist's death and said his family had been notified. Mr Irwin was married with two young children.
"It is believed that Mr Irwin collapsed after being stung by a stingray at Batt Reef off Port Douglas at about 11:00 am (0100 GMT)," a police statement quoted by AFP news agency said.
"His crew called for medical treatment and the Queensland medical helicopter responded, however Mr Irwin had died."
Mr Irwin had built up what was a small reptile park in Queensland into what is now Australia Zoo, a major centre for Australian wildlife.
Mr Irwin's documentaries were shown around the world. He was famous for handling dangerous creatures such as crocodiles, snakes and spiders, and his documentaries on his work with crocodiles drew a worldwide audience. But he also courted controversy with a series of stunts.
He sparked outrage across Australia after cradling his one-month-old son a metre away from the reptile during a show at Australia Zoo.
A probe was also launched to investigate whether Mr Irwin and his team interacted too closely with penguins and whales while filming in the Antarctic, but no action was taken.
Foreign Minister Alexander Downer praised Mr Irwin for his work to promote Australia.
"The minister knew him, was fond of him and was very, very appreciative of all the work he'd done to promote Australia overseas," Mr Downer's spokesman said.