Bindi Irwin has taken to social media to share a sweet throwback photo of herself and her younger brother Robert to celebrate National Siblings Day.
In the photo, Robert stands behind Bindi, who wrote, "Grateful to call you my brother."
Bindi also shared a more recent snap of the pair, with a heartwarming tribute to her brother that read: "Happy #NationalSiblingDay to the very best. Thank you for your support, friendship and making every day fun.
"So proud of all that you are achieving. I’ll always be here to cheer you on!"
In response, Robert commented, "Love you, Bindi!"
Fans loved the photo as well, with one user writing, "If only we all got along with our siblings the way you guys seem to... maybe it’s the advocating for a common cause."
"Little brothers are the best! Mine is like a foot taller than me now too but I still like to show him who’s boss," another joked.
"I idolised your late dad and I’m proud my children are looking up to you both as role models too," a third said.
"Best and fav siblings! You guys got through the hard times together," a fourth wrote.
"I loved to watch your parents play with you guys on tv. Nice to see you guys all grown up and looking happy," someone else said.
Many others shared that they believed the siblings' dad Steve Irwin would be "proud".
"Robert looks like his dad Steve!" a fan added.
Never miss a thing. Sign up to Yahoo Lifestyle’s daily newsletter.
Or if you have a story idea, email us at firstname.lastname@example.org.