The Chandelier singer revealed she wrote the screenplay for Sister eight years ago while chatting to reporters at the Venice Film Festival in Italy over the weekend (05-06Sep15), and now she will direct the film with the young star of her videos.

Sia said, "I was too embarrassed to tell anyone I wanted to make a movie, because I thought it would be seen as a vanity project, because I was a singer... and then last year after I made the Chandelier video, I realised that I was pretty good at directing, so I felt a little bit braver."

The pop star turned to children's book author Dalles Clayton to help her complete the screenplay, adding, "He and I spent three-and-a-half weeks just on the sofa, mapping it out."

She then asked five friends, including comedienne Whitney Cummings and actor/director Joel Edgerton, to give her feedback before deciding to make a start on the project.

Sia isn't the only member of her family making a new movie - her husband Erik Anders Lang is working on a documentary about the game of golf after a crowdfunding campaign helped him raise $50,000 (£31,000) towards filming costs.