Romeo Santos, formerly the frontman of the Bachata group Aventura, is branching out with solo album Formula. Second single “Promise” is a lush, tropical ballad that makes us feel like sipping a pina colada, but sadly does not come with one attached. It does, however, come with Usher! And we have to say that hearing the “DJ Got Us Fallin’ In Love” crooner’s smooth vocals blended with Spanish guitars, warm synths and a tinkling piano is kind of breath of fresh air. Promise (ahem) that you’ll do more songs like this in the future, Ush!