Katy Perry's Vibrant 'Birthday' Song Leaks Online

Katy Perry

Cass Bird

When Billboard got an early listen of Katy Perry's "PRISM" album last month, "Birthday" leapt out of the new batch of songs as the one with the most potential to become a smash. Although "Unconditionally" is the next single from "PRISM," let's hope the shimmering "Birthday," which leaked online on Wednesday (Oct. 16), will eventually find its way to radio as well.

"Birthday" (which can be heard here) features a subtly brilliant vocal performance from Perry, who tiptoes around the funk riffs and horn blasts without overshadowing Dr. Luke and Max Martin's production. As gleeful as the main chunk of "Birthday" becomes, the rhythmic, sensual breakdown, in which Perry coos "So let me get you in your birthday suit," just about takes the, er, cake here.

Katy Perry's 'PRISM': The Billboard Cover Story

"PRISM," due out next Tuesday (Oct. 22), has already been previewed by the officially released "Roar," "Dark Horse" and "Walking on Air." "Roar" became Perry's eighth No. 1 single on the Hot 100 chart, and the pop superstar performed the single as well as "Walking on Air" on "Saturday Night Live" last weekend.

On Thursday, Perry posted two exciting announcements on Twitter: first, the singer shared news that she has become a Cover Girl. Second, she wished her main squeeze, John Mayer, a happy birthday. Maybe the "Birthday" leak wasn't so ill-timed after all.