Why it Works: Kristin Cavallari

Why it Works: Kristin Cavallari
(Photos by PacificCoastNews.com)

How time flies. Feels like only yesterday that the most confident 17-year-old to ever walk the earth, Kristin Cavallari, was belting out Kelly Clarkson's "Since You've Been Gone" in a limo, toying with the emotions of Stephen and Talon, deriding Casey's prom dress as totally not Laguna, and regularly appearing in "is she too skinny?" Us Weekly lists. And just look at her now, seemingly dunzo with all that other nonsense. She's a 25-year-old Dancing with the Stars alum and mother-to-be, expecting a baby boy with fiancé Jay Cutler and sipping organic kale juice like a regular Reese Witherspoon, only without the Academy award.

The Dress: The very picture of innocence, Cavallari's ruffled, oversize button–emblazoned sundress has a flirty sixties appeal that offers a crazy flattering maternity silhouette. She cuts the sweetness with a pair of hepcat Ray-Ban Wayfarers.

The Shoes: You can take the girl out of the O.C., but you can't take the flip-flops off the girl. These slight, nude numbers are a minimal yet classy touch.

The Hair: It's doing something ombre-meets-Heather Locklear (the patron saint of blondes with dark roots). Whether it's a calculated fashion dare or a ban on chemically-fueled beautification rituals during this whole miracle of life phase, it gives Cavallari's new good girl image a welcome bad girl spice. 

The Juice: The emerald green drink establishes her L.A. credibility (you aren't anyone in this town if you're not downing something cayenne-spiked or spinach-infused from Pressed) and offers a flash of color in an otherwise jet black scheme.