The caption then continued: "Thank you for your incredible strength and guidance, thoughtful patience and encouragement, and above all - your unconditional love," the wildlife warrior wrote.
"You do so much for our family, and for everyone around you. It's amazing watching you effortlessly, and selflessly care for others, wildlife, humans, and our planet alike.
"I love celebrating YOU today and every day. Can't wait to make this next year truly unforgettable, filled with family, and revelling in every joyful moment we share. I love you, every minute, for all of my days. ❤️"
Brother Rob was also quick to share a birthday tribute of his own for his mum, writing a short, but similarly sweet post.
"Happy birthday mum! You'll always be the biggest inspiration and guiding light for me and Bindi. You are incredible, love you! 💙"
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The accompanying images were of a baby Rob with his white blonde locks, all rugged up for winter with a much younger Terri, and the pair almost 20 years on - Rob now a grown man.