The beautiful moment was a recreation of a photo of herself with late father Steve Irwin kissing wife Terry Irwin's baby bump while she was pregnant with their son Robert Irwin.
"Recreating a very special moment," Bindi wrote. "Third trimester love."
Bindi was just eight years old when Steve passed away, but she and Robert have been determined to carry on his legacy.
The 22-year-old announced she and Chandler were expecting their first baby together in August with a sweet photo of the pair holding a tiny wildlife warrior shirt.
"Baby Wildlife Warrior due 2021," Bindi wrote. "Chandler and I are proud to announce that we’re expecting! It’s an honour to share this special moment in our lives with you.
"Though I’m still in my first trimester, we really want you to be part of our journey from the beginning of this new life chapter. We couldn’t wait to share the news as this beautiful little being has become the most important part of our lives.
"Your support means the world to us. Please let me know your best advice and send good vibes & prayers to our little sweetheart. Love & light."
Robert Irwin's brush with croc
Meanwhile, 17-year-old Robert recently had a close call with one of the crocodiles at Australia Zoo.
“Bluey the croc putting on a big strike!" Robert captioned a post featuring the terrifying footage. "There’s nothing quite like getting to experience the power of these modern-day dinosaurs, it’s such a privilege."
Fans were left shaken by the close encounter, with one person writing: "Wow amazing, not gonna lie my heart skipped a beat there."
"Yikes! Big strike! I jumped on your behalf," another person said.
"That was a little too close for me," someone else wrote.
Others just couldn’t get over how much Robert bears a striking resemblance to his late father, Steve Irwin.
"So much like your father, Rob. Amazing to see you and Bindi grow like this and really live up to everything your dad started. He’d be so proud of you," one person commented.
"No fear, just like your dad," another said.
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