has returned to her sunny blond roots just in time for her 26th birthday in Vegas over the weekend. We've watched her transform effortlessly from a deep raven brunette to a roaring redheadher hair always looking silky and shiny. The truth is chameleon color changes can wreak havoc on your locks, especially bleaching, which strips down the cuticle leaving it vulnerable to breakage. If you're a quick change artist, wash with a mild shampoo and then use an extra creamy conditioner. Look for products tailored to color-treated hair, they'll strengthen the fibers that have left dyed hair weak and damage-prone. Finally, blondes beware: Chemicals in swimming pools can tint hair green. Use products with an SPF to guard against sun damage and chemical discoloration in the summertime.