“Our Dad, Mum’s soulmate and a superhero for us all, passed away,” the Dancing with the Stars champ wrote. “However, since this photo was taken, 18 years ago, one life ingredient has remained, unchanged, unbreakable. That is the unconditional love that is shared between my beautiful little family and the loyalty we have to each other and everyone else who has taken this journey with us.”
Irwin added that she is “endlessly grateful” for her parents and the love that surrounds her.
Irwin was 8 when her father was killed by a stingray in a freak accident.
She followed up with a second post of a more recent picture and a note about her future as an adult.
Just a few days earlier, Irwin posted a similar throwback photo in honor of her mother’s birthday.