The record will be made up of original songs, composed with the help of Adele's producer Greg Kurstin.
Atlantic Records said in a statement: "Sia is a once-in-a-generation artist. Her extraordinary gifts as a singer and songwriter, her revolutionary approach to the art of performing, her groundbreaking videos - everything she does comes from a deep wellspring of inspiration and imagination.
"Sia is that rare artist who has formed her own singular, boundless musical universe. We are so happy to welcome her into the Atlantic family and to be joining Sia on her amazing musical journey."
In other news, Sia has also announced her directorial debut, as she'll be making a film with actress Kate Hudson; a new drama titled Sister based on a one-page short story Sia wrote eight years ago.
The project will also star teen dancing sensation Maddie Ziegler, 14, originally of Dance Moms fame.
Speaking about the project at the international film festival Venice Days, she 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 realized that I was pretty good at directing, so I felt a little bit braver.
"For me, the process was basically, I work out the movie. I'll act it out, I'll have the dialogue already in my head. I can't be bothered to learn Final Draft. I'm not a technical person. Like, when I sing, I just want to sing the melody and write the lyrics."
