Is there a more hard-working pop star right now than Ariana Grande? Six months after releasing her fourth album Sweetener ... R.E.M., No Tears Left to Cry and a cover of lesser-known bass genius ...

Sweetener' arrived ... Less than one month after the album came out, the Wicked star's ex-boyfriend Mac Miller died of an accidental drug overdose. Related: Ariana Grande Makes Generous Christmas ...