Sia surprised everyone when she showed up at the Survivor live finale. Host Jeff Probst was talking to fan-favorite Tai Trang about his journey on the show when a voice called Probst's name from the crowd. Sia, wearing her trademark wig, joined the host onstage at his invitation.

"I could not let Tai go home without saying that your authenticity and care for animals really inspired me. And so, I want to donate $50,000 to you and I want to donate $50,000 to your choice of animal charity," she said.

That's right. Sia just showed up and pulled the ultimate super-fan move. Probst referred to her as a fan of the show and her donation backs that up. She mentioned that there used to be a fan favorite prize and she wanted to step in where that sponsor had left, because she was so inspired by Tai. "Thank you for showing America how to be kind to animals," she said.

For his part, Tai was clearly shocked and moved. He joined Probst and Sia on stage to thank the singer for her generosity.

"We can not be so human-centric. Without the whole ecosystem, we will be doomed sooner than we think," he said. Clearly, Sia agrees and put her money where her mouth is — even if we can't see it behind that wig.