The stars came out in Las Vegas for the 2012 Billboard Music Awards at the MGM Grand tonight. Hosts Julie Bowen and Ty Burrell kicked off the white carpet with a Jean Paul Gaultier-clad Miley Cyrus following closely behind. Nominee Taylor Swift wore red Elie Saab for the musical event, and presenter Julianne Hough chose a short Kaufman Franco dress. Alicia Keys, in long-sleeved Azzedine Alaia, had her husband, Swizz Beatz, by her side, as did performer Carrie Underwood, who looked glamorous in a sparkly Oscar de la Renta gown. Katy Perry matched her purple hair with a lilac Blumarine look and posed with her grandmother before heading inside to take the stage. Also on hand were Justin Bieber, Usher, John Legend and fiancée Chrissy Teigen, and Jordin Sparks — click through to see them all!