Dude, that's Sia. You don't know Sia? She's got the best pipes in music right now. She was the singer for Zero7, which is one the best trip-hop/downtempo groups ever. Try these:
Zero7/Sia - Destiny:
https://youtube.com/watch?v=FobL7mzRons
Sia - Blow it all away:
https://youtube.com/watch?v=r6AxgutrP4Q
Sia - Breathe Me:
https://youtube.com/watch?v=hSH7fblcGWM
Sia/Zero7 - Distractions:
https://youtube.com/watch?v=2Jj-7pYFzto
She's got a ton of great music, mostly chill stuff.