Sia has lent her hand to another high-profile album by writing a tune for Beyonce, which she thinks is her "best song".
The 'Titanium' singer-songwriter said in a set of tweets to fans that she has contributed to Beyonce's new album, but she wouldn't reveal any specific details.
She has also just written and released a song called 'Elastic Heart' for The Hunger Games: Catching Fire soundtrack.
Fans asked why she didn't give this to Beyonce, and she replied "I gave her my other best song."
The fans wondered if she talking about Standing on the Sun, which was featured on Beyonce's H&M summer wear advert. She revealed that we haven't heard it before and it will definitely be on the album.
Beyonce has written a song with Sia on new album (WENN)
This wouldn't be the first time the pair have worked together. They collaborated on 'Rise Up', which featured on the soundtrack to animated movie, Epic, which Beyonce also lent her voice to.
The 'Single Ladies' singer has not revealed much about her upcoming album despite giving the fans previews of Grown Woman, Bow Down and Standing on The Sun over the past few months. Sia, 37, has worked with a lot of high-profile singers on their albums, like Jennifer Lopez' next offering and Katy Perry with her upcoming 'Prism'.
Most recently, she went into the studio with Britney Spears to write a song for her upcoming eighth album. Britney even tweeted: "Had an AMAZING writing session today with the beautiful and talented @Sia. We wrote such a special song together." Sia then praised Brit back, writing: "your vocal on this tune is outstanding. WERK!"