Robert Irwin pens emotional tribute to his father Steve on his birthday

Robert Irwin has penned an emotional tribute to his father Steve on his birthday.

Irwin, already known for his dynamic personality on shows like I’m A Celebrity… Get Me Out Of Here!  has marked his 21st birthday.

The television personality took to Instagram on Sunday and posted a photo of his late father celebrating his own milestone birthday decades ago.

The image shows Steve, a fresh-faced young man, cutting into a vibrant birthday cake while surrounded by family.

In the caption, Irwin penned, “Today I turn 21. I was looking through the archives a few days ago and found these pictures of my dad on his 21st.”

“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.”

Moreover, Irwin expressed his gratitude for the support of his family, saying, “I am one lucky guy to be surrounded by my amazing family today. Time to celebrate!”

Known as "The Crocodile Hunter", Steve died on September 4 2006 after being pierced in the chest by a short-tail stingray barb while filming in the Great Barrier Reef with Philippe Cousteau Jr.

Irwin was just two years old at the time while his sister Bindi was eight.