Slideshow will continue in seconds. Click to skip
Back in her American Idol days, Katharine was all about flared denim and "going-out tops." Cute and youthful, sure—but not quite worthy of her killer voice and fab figure.
Jewel tones are generally flattering—except when they come in the form of an overly-ruched satin dress.
Kat's hair looked fantastic at the 2006 Billboard Music Awards, and we like the softly-draped neckline and classic peeptoe pumps—but that hemline could stand to be a few inches longer, no?
That's better! At a 2007 Golden Globes party, Katharine showcased her curves in one of the most va-va-voom LBDs we've ever seen. Ah, the magic of savvy draping.
At the premiere of The House Bunny in 2008, Kat went for an ultra-feminine look—from the sweet white ruffled dress to those blunt-cut bangs. Lovely.
Holy hair change, Batman! Katharine paired her new peroxide-blond crop with a sexy, strappy lavender gown in 2009.
In this shimmering Moschino LBD, Katharine went for a rockabilly vibe in early 2010.
At the 2012 Golden Globe Awards, the singer and actress left us speechless in this stunning nude Donna Karan dress—the first of many top-notch red carpet looks.
The Smash star was an absolute knockout in this coral sequined Elie Saab at the 2012 Met Gala.
This past May, Katharine looked flawless in this floral Dolce & Gabbana dress at the NBC Upfront Presentation. Those sideswept waves are the perfect finishing touch.