We're not sure what secret project singer/songwriter Sia and Kate Hudson are working on but if George Miller is ever looking for someone to slip into Charlize Theron's 'Mad Max' boots, he's got another option today.

The duo are currently working on a mysterious project in Los Angeles and the mystery has deepened further after an image revealing Hudson had shaved off her signature blonde locks started doing the rounds, piquing the interest of the internet and Hollywood. 

Sia was the first one to share a photo of Hudson's new buzzcut, posting a still from their shoot on Twitter with the caption "My girl @Katehudson being a delight on set."

And it wasn't long until the internet took notice of the actress' newly shorn head and offering a closer look.

Hudson took to Instagram to share Sia's photo of her and her new 'do, complimenting her "beautiful director" and captioning the image 'Freedom'. Whether that's a statement on the new haircut or the name of the project remains to be seen.