American Music Awards' Style Stars

Before performing a country version of “Irreplaceable” with Sugarland, the singer sizzled in a skintight satin Tina Knowles for House of Deréon gown and more than one million dollars of Lorraine Schwartz diamonds on the red carpet.

The singer stood out on the red carpet in a boldly patterned one-shoulder sequined Ungaro dress, Fendi heels and oversized Lorraine Schwartz earrings.

The night’s big winner showed off her fit figure in a white lace Georges Chakra mini dress and strappy Rene Caovilla heels – accessorized with a Mary Norton clutch and Mikimoto pearl earrings.

Before changing into a dramatic Zac Posen for her performance, the singer sparkled on the red carpet in a black velvet and Swarovski crystal-encrusted Armani Privé dress.

The teen sensation looked all grown-up in a red strapless Nuj Novakhett minidress, Christian Louboutin pumps and a Rebecca Minkoff clutch.

The singer showed that less is more in her black Dsquared halter dress – the designers make a cameo in her “Clumsy” video!

Minus boyfriend Zac Efron, the High School Musical star is the night’s golden girl in her shimmering Marc Bouwer minidress, Rene Caovilla sandals and long curls.

The singer dazzled in a glamorous sequined Giorgio Armani dress, Ippolita crystal earrings, smoky eyes and soft curls.

Before accepting the award for favorite soundtrack, the High School Musical 2 actress lit up the red carpet in a silver sequined Mandalay dress, Chanel jewelry, and Stuart Weitzman shoes

The often-punky singer glammed up for the red carpet in a ruched Dolce & Gabbana dress – but still showed off her daring pink streaks.

The Samantha Who? star was the epitome of chic in her origami pleated purple Donna Karan dress, Neil Lane platinum jewels and sleek bob.