Robert Irwin was just 2 when Steve Irwin died. On his 21st birthday, he honoured his father.

In December 2003, the world watched on as Terri Irwin and Steve Irwin announced the birth of their second child, a younger brother to five-year-old Bindi.

Robert Irwin, named for his grandfather, was beloved by his entire family from the moment he was born.

He would go on to become one of the most recognisable faces in Australia; rubbing shoulders with the likes of Prince William through his climate action, fighting to protect local ecosystems and animals, and breaking records as the youngest ever nominee for the coveted Gold Logie Award.

Watch the moment Bindi met her little brother. Story continues after video.

But when he was just two years old, Robert suffered the unimaginable loss of his father.

On September 4, 2006, Steve was pierced in the chest by a short-tail stingray barb while filming an underwater documentary on the Great Barrier Reef. His untimely death was met with overwhelming grief not just in Australia, but around the world.

His lasting legacy of conservation and environmentalism lives on in the work of his family. In particular, Robert stepped into his father's khaki work boots at Australia Zoo.

In every step he takes, Robert is reminiscent of his late father. But he isn't just routinely compared to Steve, he's also asked about him all the time — by fans and media alike.

Robert has said it's the "honour of his lifetime" to carry on Steve's work. And that, in many ways, it keeps them close.

"You will never move on," Robert said of his grief, on the Mental As Anyone podcast. "But it's this shadow that you've always got that eventually, instead of it just being within you, consuming every day, it walks beside you."

Robert continues his father's legacy. Image: Instagram/@robertirwinphotography.

He admits being in the public eye from such a young age, and having to come to terms with grief in front of the world, added 'an extra element of odd.' But that he loves 'getting little pieces' of his father back through those that knew him.

"I'm very lucky, because I'm still around a lot of the people that were closest to Dad, the people who influenced my life most, and so it's just constant stories. It's the little faded memories that I've got," he said on the podcast.

"Having lost someone at a very young age, I love getting little pieces of him back."

Robert says it's an 'honour' to carry on his dad's work. Image: Instagram/@robertirwinphotography.

On his 21st birthday, December 1, 2024, Robert shared a tribute to his dad.

"Today I turn 21. I was looking through the archives a few days ago, and I found these pictures of my dad on his 21st," Robert wrote in his caption.

"It can be hard to celebrate the milestones when there's someone missing, but I will carry his memory and passion with me in this new chapter of life. I am one lucky guy to be surrounded by my amazing family today."

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A post shared by Robert Irwin (@robertirwinphotography)

Up next for Robert, he'll return to his hosting gig alongside Julia Morris on I'm A Celebrity Get Me Out Of Here. With his undeniable charm and humour, his on-screen appearances usually bring about more comparisons to his late dad.

Robert was nominated for the Gold Logie Award for his hosting of I'm A Celeb this year.

At the time, he told The Australian Women's Weekly he was simply honoured to be using his new platform to put his conservation work out there.

"Dad used to say, 'I don't care if people remember me. But I do care if people remember my message.' This is a great platform to spread positivity, to hopefully lead by example, and to show other young people to follow your dreams, and follow your passion.

"It's funny to think that all this all started with one bloke in Beerwah in the '70s, who then started Australia Zoo and then created a legacy. To be up for [the Gold Logie] is very meaningful and it's a win for conservation either way."

Feature Image: Instagram.