SAN FRANCISCO, CA - AUGUST 13: Sia performs on Day 2 of Outside Lands Music Festival at Golden Gate Park on August 13, 2011 in San Francisco, California. (Photo by Steve Jennings/WireImage)

Sia has co-written great pop songs for a number of artists -- including Britney Spears, Katy Perry, David Guetta, Flo Rida and Rihanna -- but she decided to keep one for herself: "Chandelier," the first solo single the Australian singer has released in four years, and the best Rihanna song of 2014.

"I usually think, 'Oh this would work for Rihanna,' or 'this would be a good one for [Britney] or Katy,'" Sia told Ryan Seacrest. "But this time I was like, 'Uh oh, I think I just wrote a full-blown pop song for myself by accident!'"