Sia is usually shy about showing her face - but she was perfectly happy to share a photo of her bare butt on Twitter this week.
The wig-wearing weirdo learned that some creepy site was selling nude pictures of her, taken from behind, so she decided to beat them at their own game - by posting one on her own Twitter account. The photo, taken from just a few feet away, shows Sia on a balcony of some sort, walking away from the camera stark naked.
In the caption, she wrote "Someone is apparently trying to sell naked photos of me to my fans. Save your money, here it is for free. Everyday is Christmas!"