The 15-year-old British actress took to Instagram Sunday after spending the "most magical day" with the 20-year-old television personality and conservationist in Australia.
Brown shared a photo of herself with Bindi and the star's brother, Robert Irwin, at the zoo.
She couldn't help but gush about the pair and her experience in the caption.
"wow. wow. wow. the most magical day with these special souls," Brown wrote.
"thank you so much for what you do for the world. animals at your zoo receive love and care every single day with your loving keepers. and thank you for letting me come visit the zoo and see animals that I'd never thought I'd see. best day ever," she said.
Bindi, the daughter of late "Crocodile Hunter" star Steve Irwin, posted a picture with Brown and a giraffe on her own account.
"Thank you for visiting today beautiful @milliebobbybrown," she wrote. "You are a light in this world, keep shining xx."
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KIIS 101.1 said Brown is filming the movie "Godzilla: King of the Monsters" in Australia.
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