Steve Irwin's Son Robert Reflects on 'Heartbreaking' 21st Birthday 18 Years After His Dad's Death: 'I'll Never Be Complete'

Robert Irwin is reflecting on father Steve Irwin’s legacy on his 21st birthday.

In a new interview, the youngster — who turned a year older on November 30 — explained how he is still mourning his dad almost two decades after the TV star’s tragic passing.

"It can be heartbreaking. I can’t beat around the bush," Robert confessed. "It’s really hard, particularly when it’s those milestones. It’s difficult navigating that without a father figure. But I have to really praise my entire family and particularly my mum on the way in which she’s stepped up to make sure that – while there will always be part of myself missing, and I’ll never be complete – I never felt like I missed out on anything."

He continued: "I hope that somewhere, somehow, he knows I’m trying to make him proud."

On his birthday, Robert made a sweet social media post about missing his father.

"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," he wrote. "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. Time to celebrate!"

Steve died in 2006 after being fatally stung by a sting ray in the Great Barrier Reef. The star was filming the documentary series Ocean's Deadliest when the incident ended his life. Robert was just 2 years old at the time, while his sister, Bindi, was 8. Before his passing, Steve and wife Terri were married for 14 years.

Since his father’s demise, Robert has tried to keep his father’s memory alive.

"What dad really instilled in me — because I was very young when he passed away, but he was there so much of my early years — [was that] he was so passionate about being there for myself and my sister all the time," the Australian conservationist told People in 2022. "He was the most devoted dad. I think that passion that he had and just that absolute zest for life is just my foundation. I like to say it's a factory setting for me.”

In honor of "The Crocodile Hunter," Robert also released his book, Robert Irwin's Australia, in 2022.

"My dad was a very, very passionate photographer," Robert said of the tome, which highlights Steve’s work. "It sort of runs in the family. He was equally enthusiastic behind the lens as in front of it. And it's just always kind of been there and been part of my life."

Robert worked on the book for years, noting the idea "was always something that was kind of simmering in the background."

"I thought, 'You know what? I want to do this justice and make something that really celebrates what has become my own individual way to carry on my father's legacy,'" he added.