Bindi Irwin and brother Robert share emotional tributes to late dad Steve on his 64th birthday

"Would have been your birthday today. Love you, miss you… thank you for being a guiding light and inspiration every day," Robert wrote on his own Instagram. 

Fans flooded the comment section with words of encouragement. 

"So much of what we loved about your father lives on in you," one person wrote on Robert's post. "I've no doubt that he is incredibly proud of the man you've become! You're a wonderful role model!"

"He was such a great person and his passion for wildlife and love for his family shines on through you all," another commented on Bindi's post. 

"Coming over from Australia, I didn't know how it would go. I didn't think I'd make it this far, because I didn't realize how incredibly supportive America would be," he said. "It's impossible to put into words how much that has meant to me, because what I represent is so much more than just a dance."

"When I step into the ballroom, I'm representing a legacy that my dad [Steve Irwin] created with my mom. I'm representing everything I stand for, not only as a wildlife conservationist, but also as someone who is working really hard to try and spread some positivity and passion," he continued. "I want to be a role model for young people."

"The fact that America has invited us back every week all the way to the end, it means that what I stand for is being heard and that is incredible," he added. "I am so grateful. All of the challenges in the rehearsal studio, learning each new dance, have been worth it when I hear about how a dance resonated with people you know… being able to bare my heart and soul to America is scary, but it has been the most beautiful experience ever, because everybody has been with me on this journey and I feel like I've gained a whole new family over here."