Billboard Music Awards 2012: What the Stars Wore!

Carrie Underwood, Taylor Swift, and Katy Perry Credit: Frazer Harrison/Getty; Denise Truscello/ (2)

Unlike Taylor Swift and Jordin Sparks, Miley Cyrus doesn't know the meaning of "event appropriate."

The 19-year-old "Can't Be Tamed" singer risked a nip slip in a cleavage-baring Jean Paul Gaultier jacket, Jacquie Aiche jewels and Christian Louboutin heels. Swift, 22, looked radiant in a red Elie Saab gown, while Sparks, also 22, showed off her slim figure in a Diane von Furstenberg dress.

"Wide Awake" singer Katy Perry, 27, brought her grandmother, 91, as her date. The single star dazzled in a backless Blumarine gown. Carrie Underwood, 29, wore head-to-toe Oscar de la Renta.

Other stars at the event include Julianne Hough (in Kaufman Franco), Alicia Keys (in Azzedine Alaia), Julie Bowen (in Doo.Ri), Zooey Deschanel (in Moschino) and Nelly Furtado (in Alberta Ferretti).

To see more red carpet looks, check out the gallery now!