Sia isn't playing. She just keeps releasing smash after smash from her anticipated forthcoming album, which is set for official release on January 29. This time, the wigged songstress has let 'Unstoppable' fly and as expected, it's a hair-raising power ballad about strength.

'Unstoppable' follows previously-shared songs from This Is Acting - 'Reaper' (co-written and co-produced with Kanye West), 'Alive,' 'Bird Set Free,' 'One Million Bullets,' and 'Cheap Thrills.'