SIA was the principal songwriter for RIHANNA'S song "Diamonds" . . . the one where Rihanna sings, quote, "Shine bright like a diamond" over and over and over again. 24 times, to be exact.
It sure sounds like Sia spent less than 15 minutes writing the whole song. And that's because she DID. Sia told the "New York Times" the song took her 14 minutes to write..
Then she recorded a demo and passed it on to Rihanna, who copied her inflections so closely that when Sia first heard the final version, she thought it was still her vocal.
She says, quote, "She could've done it her own way, but I think she really genuinely liked the way it was."