Real Beauty's Ultimate Sunglass Challenge

Those with heart-shaped faces, like Reese Witherspoon, may also have wider foreheads. Instead of opting for a style with your hair parted down the middle, draw attention to your cheekbones with side-swept bangs and long layers.

If you have a heart-shaped face, stay away from oversized shades (think Nicole Richie or the Olsen twins) because they will cover the top half of your face and bring even more attention to your forehead.

From left to right: Wet Seal Oval Tortoise, $7.50, wetseal.com; Fossil Angie Sun, $50, fossil.com; ELLE, $26, kohls.com

Oval faces are the most proportionate, meaning they can wear almost any kind of cut. If you want to find out if you have an oval-shaped face, measure the length and width of your face with a measuring tape. The length should be one and a half times the width.

Jessica Alba is proof that oval faces are the most versatile. Whether her hair is blonde, brunette, long, or short, she always looks great!

Oval-face shapes can wear a variety of different sunglass styles. Stay away from oversized frames though, since oval faces tend to have smaller features, and larger frames can make your face look smaller than it really is.

From left to right: Nine West Mod Oval Sunglasses, $38, ninewest.com; Simply Vera aviators, $34, kohls.com; Apt 9, $26, kohls.com

If your face is as wide as it is long, you have a round face. The updo should be your go-to hairstyle. It will make your cheekbones appear longer, and the added height will even out your rounder dimensions.

Layers and long, sweeping bangs like Kirsten Dunst's are perfect for round-face shapes. Avoid super short styles to keep your face as slim-looking as possible.

When choosing sunglasses, make sure you opt for a pair that's the same size as your face with sculpted angles. If you choose a pair that's narrower, your face will appear rounder than it already is.

From left to right: Coach Poppy Rectangle Sunglasses, $88, coach.com; Sonoma Life + Style Sunglasses, $26, kohls.com; White Rimmed Aviators, $9.99, marshallsonline.com

Angular cheeks and jaw give your face a square shaped. To soften these features, add texture to your hair with curls, braids, or frayed ends.

If you're going to opt for long layers like Sandra Bullock, make sure they start at the jaw line to round out your facial features.

Oval and cat-eye frames tend to work best for this face shape. The rounded edges soften the angular planes of your face.

From left to right: Fossil Marla Sunglasses, $40, fossil.com; Nine West Rectangle Sunglasses, $36, ninewest.com; Daisy Fuentes Sunglasses, $26, kohls.com