Hudgens posted this pic on Instagram when she turned her signature bleached ombré hair into a cool aquatic color.

Try this: Rita Hazan Pop Color in Blue, $18, is an easy-to-use spray-in color that washes right out. "What's quite good is to get the hair smooth and then spray it at a little bit of a distance, working downwards," Kahlani says of getting the look. "[Spray it] heavier on the ends so you get a more intense color."

If you don't naturally have a wave to your hair, but want to copy Hudgens' curls, Kahlani recommends heat styling before you add color. "Heat removes the color, so do all your prep before sprays and chalks," she says.

Who it works on: Light and ashy blondes and dark hair with bleached ombré can get the pale blue shade when sprayed on lightly, while dark haired girls will have to spray the product on more heavily to get a turquoise shade.

No stranger to experimenting with electric hues, Lovato's latest shade of purple is a fun pop of color that's surprisingly easy to get at home.

Try this: L'Oréal Professionnel Hairchalk in First Date Violet, $24, is applied like a dye on dried and styled hair, and will last through several shampoos. Apply the color to your hair in sections -- remember, the more heavily you saturate the hair, the longer it will last. After each section, allow the color to dry for one minute, then brush through while lightly blow-drying.

Who it works on: The pearlescent pigment technology means L'Oréal Professionnel Hairchalk shows up on every hair color. The downside is, unless you employ Kahlani's dish soap tip, the color is designed to last for four to five shampoos.

We love this runway look because it's just so easy.

Try this: Clip in Sultra Hair Palette Color Clip-In Hair Extensions, $9, which come in bright and pastel shades (try them in Lapis Blue for the look at Hervé Léger).

Who it works on: The reason these clip-ins are so fun is because they can be used on any hair color and they work in a snap. Clip them into your ponytail, or if you're having a hard time getting the color sprays or chalks to show up on dark brown and black hair, clip these underneath your hair for the dip-dye effect -- you can even heat style them.