Credit: Steve Granitz/ (2)

Between her on-stage concert looks to her red carpet ensembles, Selena Gomez is drilling home the fact that her days of Disney darling are behind her.

At the 2011 American Music Awards in Los Angeles Sunday, the 19-year-old worked the Nokia Theatre carpet in a slinky, pewter satin Giorgio Armani number, which she complemented with a glittering purse and matching Jimmy Choo sandals.

The "Love You Like a Love Song" singer showed some skin in the glam gown's plunging, cleavage-baring halter top, low-cut back and thigh-high slit.

Of course, her best accessory was her boyfriend, Justin Bieber, who also was going for the grown-up look in a dapper black tuxedo and a side-slicked hairstyle. When the couple was finished posing for pics on the red carpet, the 17-year-old teen heartthrob even carried his girl's trailing train for her as they exited.

Gomez, who hosted the MTV Europe Music Awards earlier this month, didn't perform during the night, but she was spotted having a blast, singing along to Nicki Minaj's "Super Bass" with pal Taylor Swift and proudly watching Bieber perform "Mistletoe" from the front row.