You may have dyed your hair every shade imaginable: red, brunette, blond, etc. But have you gone rainbow yet? Celebrities can't stop testing out this hot hair trend, taking on colors like navy (Nicole Richie ), green (Katy Perry ), and blue (Demi Lovato). Whether you add a sharp shade to your bangs, into your braid, or over your whole head, it's the perfect way to stand out in a crowd. So what are you waiting for? Start scrolling and get some serious Crayola hair inspiration! Then, watch our video on this must-try trend .
— Additional reporting by Lauren Levinson
Source: Instagram user hilaryduff 
Shortly after transforming into a blue-haired mermaid goddess, Hilary switched up her strands to this gorgeous, faded fuchsia hue.
In anticipation of turning 30, Lily went to colorist Alex Brownsell at Bleach  for a watermelon-hued dye job. Do you think it glows under black light?
Julianne dubbed this pastel pink hair color a "unicorn" shade. The hair color update comes just in time for this weekend's music festival.
Girls star Zosia Mamet traded her platinum blond locks for silvery strands and showed off the new look at an appearance last night in New York for A Most Violent Year.
The That's So Raven star revealed this pastel hue on Instagram with the caption "Yes, peach for the holidays . . . #unicorn #5thelement #holidaypumpkin."
Tori shared a sneak peek of her new platinum-gray dip-dye job on Instagram before debuting it on the Today show.
Coif chameleon Kylie Jenner showed off her new teal tresses with a pensive photo on Instagram.
At her House of Harlow  1960 jewelry launch, Nicole's navy mane was a stark contrast to her white blouse.
Lena celebrated the Canadian segment of her book tour with a new hair color. The mint green will likely bring her good luck along the way.
To show her support for friends and family with breast cancer, Kate is wearing her pink proud this month.
Source: Instagram user katehudson 
Jennifer posed with her new lilac locks for an Instagram selfie.
Source: Instagram user cesar4styles 
Vanessa regrammed the photo her colorist Riawna Capri posted to Instagram, claiming she dyed her hair in honor of Halloween .
Source: Instagram user riawnacapri 
Just a few weeks after flaunting blond hair at her wedding , Ashley coyly showed off new lavender locks on her Instagram account.
Source: Instagram user ashleytisdale 
Kylie's ever-changing locks have yet again switched gears — she added a sea blue ombré to her long extensions.
Katy showed off her hot-pink hair and her sense of humor by comparing this new dye job to Animal from The Muppet Show.
Rita attended the launch of her new line for Adidas  in South Korea rocking pastel rainbow accents in her platinum locks.
Girls star Jemima rocked strawberry strands to opening night at the Metropolitan Opera.
Orange Is the New Black's Dascha Polanco attended Spring 2015 New York Fashion Week with absolutely stunning gray and lilac ombré locks.
This Summer, Kesha has tried just about every hair color under the sun — blue, pink, purple, turquoise, green — and now she's combining them all in a rainbow hue. But the question is: how long will this mermaid mulitihue look last?
Now that Anna's no longer baring fangs on True Blood, she headed to Aura Friedman at Sally Hershberger  to live out her mermaid-hair fantasies.
Disney star Debby took to Instagram to show the world her hair-dyeing experiment with grape Kool-Aid.
Demi has become synonymous with hot hair hues . Her latest dye 'do: 50 shades of purple. She revealed the look on Instagram with the hashtag "ReallyDontCare."
Source: Instagram user ddlovato 
Raven hit the all-in-one warm-hues combo when she mixed pink, purple, and red tones in her lob.
Source: Instagram user ravensymonecp 
Here's another recent look from Demi: she showed how to fade brunette into purple into gray.
We were convinced Kylie would be Kim Kardashian 's "something blue" when she revealed this aqua hair on Instagram before the wedding  of the year!
Source: Instagram user kyliejenner 
Festival season means floral hair crowns and colorful tresses. Vanessa played that out perfectly when she rocked this mermaid look.
Source: Instagram user vanessahudgens 
Orange striped bangs looked totally unexpected on Lily.
Source: Instagram user lilyallen 
Why wear hot pink lips if you can sport the color in your hair instead? Rumer had the right idea with this one.
Source: Instagram user ruelarue 
The model showed off dreamy, textured purple locks with a hazy filter.
Source: Instagram user realbarbarapalvin 
Rihanna  was definitely thinking pink when she wore a pixie and nails in the matching hue.
Source: Twitter user Rihanna 
Rita offered the ideal July 4 idea: firecracker-popsicle-colored hair.
Source: Instagram user andylecomptesalon 
Demi did it again — this time with fierce pink hair and a bold lip.
Source: Instagram user ddlovato 
The singer juxtaposed pastel hair with dark, heavy eyeliner.
Source: Instagram user iiswhoiis 
Of course Lady Gaga  took the neon route on the hair-color spectrum.
Source: Instagram user Lady Gaga 
Alexa Chung combined two top trends at once: braids  and rainbow hair.
Source: Instagram user chungalexa 
LC caught on to the color craze when she dyed her blond tips bright pink.
Source: Instagram user laurenconrad 
Hayden captured the rainbow in her hair in this 2012 Twitter photo and captioned it, "Me and my BF Allie finally gettin some play time."
Source: Twitter user Hayden Panettiere 
Katy added a sea-green pigment to her waves.
Source: Instagram user katyperry 
Nicole managed to make purple look totally sophisticated.
Source: Instagram user nicolerichie 
The star showed off her blue hair not once, not twice, but in four different selfie shots. Only Demi . . .
Jourdan showed off new pastel strands on Instagram, dubbing her hair "Coachella ready."