Digital perming or "hot" perming is a curling technique that originated in Japan and has since become increasingly popular worldwide. Although the chemicals used are very similar, unlike a traditional perm, digital curls are most prominent when dry, which obviates the need for heat styling, and the curls produced using a digital perm are larger and softer, which is more in keeping with current hair trends. If you want big, glam curls, and you don't mind the expense (a digi perm can run upwards of $200), it could be an excellent option for you. (No word on whether Leighton's had one, but you could get her look with one.) One caveat, though: if you have fine hair or dye regularly, make sure you consult with a knowledgeable stylist, because digital perms can be too harsh on thin or chemically altered hair.

Source: WireImage