Credit: Rodrigo Varela/WireImage

She's no Disney darling anymore.

At Thursday's 12th Annual Latin Grammy Awards in Las Vegas, pop star Demi Lovato, 19, stunned onlookers when she debuted a dramatically more mature look. Wearing a cleavage-baring magenta Roland Mouret gown, the "Skyscraper" singer oozed confidence on the red carpet.

Her only woe? "I'm bummed that my red hair didn't stay very well," she tweeted.

Lovato -- who performed with singer Pablo Alboran during the show -- recently told Latina magazine that it's been her goal to attend the Grammys.

"I don't want to go unless I'm nominated, presenting or performing. It's my lifetime goal to be able to say I'm nominated," she said. "So I really want to make that happen."