Sia Rihanna Unstoppable -

Rihanna recorded it for her 2012 album Unapologetic . Producers: Benny Blanco and Stargate.

This song was released on Sia’s 2016 album This Is Acting . The album's concept was based on songs Sia wrote for other artists (like Adele or Rihanna) that they ultimately passed on. Sia Furler, Christopher Braide. Producer: Jesse Shatkin. Release Date: January 21, 2016. Sia Rihanna Unstoppable

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 Rihanna recorded it for her 2012 album Unapologetic

Sia wrote the lyrics and melody for this track in just 14 minutes. The album's concept was based on songs Sia

This is likely the song you are thinking of, as it is the most famous collaboration between the two.