Like her pillowy mouth and hourglass curves, Johansson’s messy, just-rolled-out-of-bed bob is pure bombshell. Ask 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, add volumizing mousse to damp hair and let it air-dry. Touch up random sections with a curling iron and finish with a beach spray.