Sia is no stranger to penning lyrics for other artists but this time she's given all creative control to Kanye West, who's written her latest song "Reaper". Originally penned for Rihanna, the Australian singer teamed up with West who wrote and produced the song, which has just been released and will feature on her upcoming album This Is Acting.

But Sia too had reservations about "Reaper". "I'm not emotionally attached to it," she said. "I think it's a good, a fun song, but I didn't anticipate it being on the record. But my manager really likes it so I put it on for him." This is the second time that Sia and West have worked together, following last year's "Wolves".

This Is Acting will be released January 29 and is available for pre-order on iTunes now.