Sia wrote the lyrics and melody for this track in just 14 minutes.
There seems to be a bit of a mix-up between these two artists. Sia's hit song was not recorded by Rihanna, nor did Rihanna write it. However, the two have a very famous connection through the song "Diamonds." "Unstoppable" by Sia Sia Rihanna Unstoppable
This is likely the song you are thinking of, as it is the most famous collaboration between the two. Sia wrote the lyrics and melody for this
Rihanna famously mimicked Sia's vocal demo almost exactly, which Sia later said she found incredibly flattering. You can read more about the production on the Diamonds Wikipedia page . However, the two have a very famous connection
While many songs on this album were intended for others, Sia has not publicly confirmed if "Unstoppable" was specifically written for Rihanna. "Diamonds" by Rihanna
