If there's any hair justice, Aniston's "lob"—or long bob—will end up being more imitated than the "Rachel." "This is one of the new classics," says hairstylist Tommy Buckett of the Marie Robinson Salon. "It's chic and superflattering thanks to all the length in the front, and it can soften a strong jaw like Jen's or thin out a round face." The term "lob" is hardly exact, so be clear about your desired length—or better yet, bring a photo to your salon appointment. Then reiterate a few points: "Ask for piecey layers that are longer in the front," says hairstylist Matt Fugate of the Sally Hershberger Salon in New York City. 

Like her pillowy mouth and hourglass curves, Johansson's messy, just-rolled-out-of-bed bob is pure bombshell. Fugate recommends "asking your stylist to chop up and razor the ends and to check the length so it swings freely above the shoulders." This cut looks good on those with medium or wavy hair and any face shape. (If your face is round, keep the front pieces a little longer to slim it.) To play up the texture, Fugate suggests adding volumizing mousse to damp hair and letting it air-dry.  Touch up random sections with a curling iron and finish with a beach spray. 

Whether beaching it in Forgetting Sarah Marshall, stalking ballerinas in Black Swan, or caught out by paparazzi, Mila Kunis always looks effortlessly sexy. We can't all have her smolder, but her long, layered hairstyle is another story: It's great on all but the finest hair. "This type of cut is very versatile," says Buckett. No matter what your texture—wavy, straight, or curly—make sure your stylist snips away at the ends of each layer, so they're wispy and a bit rough; otherwise, the cut will lose its soft, seductive quality.

Williams's flirty crop proves that short hair needn't be tomboyish. "Her pixie is really sexy thanks to the longer hair at the crown, and the soft and wispy back and side pieces," says Fugate. This cut works best for fine or medium textures—coarse, curly, or thick hair would get too puffy—and on those with heart or oval-shaped faces. Fugate recommends blow-drying with your hands, rather than a brush, and using fingers to smooth the hair down. Finish with a little nonstick wax or pomade for both hold and shine.

Maggie Q usually tames her hair into a sleek sheet, but at the People's Choice Awards, she let loose—showing off a great cut for her natural texture. "You have to treat curly hair like a sculpture, molding it subtly rather than doing chunky cutting and creating harsh lines," Fugate explains. Ask your stylist to start layering at the shoulders and to streamline the sides to avoid a puffy, pyramid effect. Styling is simple: Spritz a lightweight, leave-in conditioner through damp hair, and let it air-dry. For enhanced definition and shine, wrap sections of hair around a curling iron—but only at midshaft. Leaving out the roots and ends maintains the beachy, relaxed vibe.

A knockout like Washington would probably look gorgeous with a buzz cut, but her new side-swept bangs and wavy layers are the ultimate frame for her face. Fugate points out that the shaggy gradation can also add body to medium hair: "By layering it, you get the illusion that the hair is thicker than it is," he explains. (The opposite is actually true if hair is very fine: Snipping into it too much will only make strands look sparser.) Play around with the bangs and part—if you have a long face, a middle part may be most flattering.

If we had to choose between marrying a prince and having Kate Middleton's hair, we might just pick the mane (it doesn't come with etiquette rules or exacting in-laws). The cut itself is simple—"just classic, long layers with some framing around the face," says Buckett, who recommends asking your stylist for exactly that, and specifying that the layers also be chunky and thick at the ends. The bounce and lift come from styling: "Prep hair with a polishing cream or serum, blow your hair out with a round brush, and then use hot or Velcro rollers to give it volume." Women with medium to thick hair—either wavy or straight—look best with a cut like this, since it thins out your natural texture.

For young stars, hairstyles are easy come, easy go—and just like that, Easy A's Emma Stone ditched her red, sideswept look for a blonde shag with bangs. "This feels fresh because of its allover piece-y quality," says Fugate. Ask your stylist for heavy bangs that start at the outer corners of your eyes, with the ends razored to lighten them up and lots of layers throughout the rest of the hair, especially around the face. (When you pull your hair back, there will be loose strands that add shape and character to a simple ponytail or bun.) This cut suits almost anyone—just steer clear if you have a cowlick or tight, coarse curls.

Danes's so-called bob has morphed over the years, and her most recent chop is the prettiest yet. "The layers open up her face, so it's really flattering," says Fugate, who has worked with Danes. "This cut is particularly good for women with fine hair who don't want to go too short." To get the look, ask for a mid-length cut with strong layers that start at the cheekbones. When styling, prep hair with a lightweight volumizing product and blow-dry with a large, round brush. Finish with a dab of shine serum.