She wrote songs for Katy Perry, Britney Spears and Rihanna, but no one knew her face until a few months ago. Well, the fact that she used to wear wigs bigger than her head wasn’t helping! We’re talking about Sia, Australian superstar who recently celebrated her 40th birthday and decided to gift herself with a new album: This is Acting (which includes top hits Alive and Bird Set Free) will be released today, January 29th, 2016. The singer has been on the scenes since the end of the 1990’s but she reached great success with Chandelier, the smash hit song featuring an even more viral video that brought little Maddie Ziegler into the limelight. Wishing her a happy birthday and good luck, we created a gallery with her best looks, including those in which she wears her infamous wigs! What’s your favorite? Do you prefer her with or without?