Blonde vs brunette: Celebrity hair transformations

Allison Williams said goodbye to her Girls character Marnie with a new look in early 2017. The actress shared a photo of her new blonder locks writing: "Here it is IRL. Still getting used to it, but I dig it. Thank you @auracolorist and @rebekahforecast for helping me say goodbye to Marnie -- and to @allure for the nudge!" Photo: Instagram/@aw

Olivia Wilde didn't just switch up her hair color to platinum blonde, she also chopped off several inches which she debuted on Instagram in February 2017. Photo: Instagram/@oliviawilde

Niall Horan went in another direction coloring his hair dark brown in 2017. Photos: WireImage/Getty Images

Uma Thurman's dark hair made her eyes pop when she debuted the look, right, at the Pirelli calendar launch in November 2016. Photos: Getty Images

Orlando Bloom tried out light-hued locks, right, in November 2016. Photo: Getty Images

Zoe Kravitz swapped her long, dark braids for a shorter blonde style in autumn 2016. Photos: PA, Instagram/@zoeisabellakravitz

Famous brunette Demi Lovato briefly went blonde, left, in fall 2016. Photos: Instagram/@ddlovato

Supermodel Coco Rocha indulged in the platinum blonde trend with a new bob in autumn 2016. Photos: Dennis Van Tine/Geisler-Fotopres / DPA/PA Images/Natasha Harri via Instagram/cocorocha

Kimberly Perry went full blonde, with her all-over highlights giving her hair summery hue. Photo: Instagram/@thekimberlyperry/Getty Images

Gabrielle Union added an ombre touch by slowly going lighter towards the ends of her hair, mixed with glowing highlights throughout.
Photo: Getty/Instagram

Gina Rodriguez flipped over to the light side! She added honey-colored highlightsto her choppy bob. Photo: Getty Images/Instagram

Miles Teller is almost unrecognizable as a blond! He ditched his signature dark crop for this lighter look.
Photo: Getty Images

Jennifer Lawrence went from dirty blond to platinum, for some major old Hollywood glam. Photo: Getty Images

Kim Kardashian is famously known for her signature dark, middle-parted hair, so she had fans buzzing when she did a complete 180 with a platinum wig. Photo: Getty Images

Anne Hathaway's tried everything! From long to short, blonde and brunette the Devil Wear's Prada star can do it all.
Photo: Getty Images

Brunette actress Lucy Hale achieved the perfect summer shade with a lighter base and gorgeous highlights. Photo: Getty Images/Instagram

Demi Lovato isn't afraid to rock any hair color! Her dark eyes pop with both blonde hair and brunette. Photo: Getty Images

Sarah Michelle Gellar changed things up and went blonde, with this reverse ombre look – light at the top and dark blonde at the ends. Photo: Getty Images

Lauren Conrad has been doing ombre from the start! She changed things up, though, by saying goodbye to blonde ends, and substituting it for a light brown shade throughout. Photo: Getty Images

Khloe Kardashian chopped her long locks off and added more blonde to her hair for a complete makeover. Photo: Getty Images

Margot Robbie traded in her signature locks for a smoldering brunette look.
Photo: Getty Images

Elizabeth Olsen looks great with both blonde and brunette hair, both with her trademark Olsen sister waves. Photo: Getty Images

Katy Perry has gone from her dark hair to blonde, blue, and every other color of the rainbow. She added blue highlights to her platinum blond hair for a fun twist.
Photo: Getty Images

Nicole Richie is a fearless trendsetter and that also applies to her chameleonic hairstyles. Photo: Getty Images

Kate Moss stuck to her natural tone during her 90's supermodel days, which the icon has evolved into a blonde style. Photo: Getty Images

Cameron Diaz traded in her signature blonde for a pretty amber-toned brown color.
Photo: Getty Images

Charlize Theron kept a lighter shade, though she's gone from dirty blonde to full platinum.
Photo: Getty Images

Beyonce is always glowing from head to toe. She's tried every look and style imaginable, so it's not a surprise she's gone from full blonde highlights to a more toned-down light brunette.
Photo: Getty Images

Kylie Minogue wasn't afraid to trade her signature sunny hair color for a deeper shade. Photo: Getty Images

Rihanna transforms her look all the time and looks fabulous doing it! Of course the singer looks absolutely amazing whether she's full blonde or brunette, and she's sure to be having fun either way!
Photo: Getty Images

Victoria Beckham spiced up her life by going from super dark to super blonde and back again. Photo: Getty Images

Sienna Miller once switched up her trademark boho blonde look for a more subdued brown shade.
Photo: Getty Images

Britney Spears took us by surprise when she went brunette years ago, as she's best known for her pop star style blonde tresses.
Photo: Getty Images

Carey Mulligan brings out different features with different hair colors. A pretty, chestnut brown color brings out the warmth in her eyes, while bleach blonde is great for rocking bright lips.
Photo: Getty Images

Dakota Johnson has no boundaries when it comes to hair, she's gone Fifty Shades of both blonde and brunette.
Photo: Getty Images

Emma Stone is best known for her signature red hair, but she completely changed the game by going super blonde and later trying a dark brunette look.
Photo: Getty Images

Jenny McCarthy is famously a blonde bombshell, but she's also tried out brunette! Photo: Getty Images

Jessica Biel has been a brunette for a while, but she did try life as a blonde at one point!
Photo: Getty Images

Rachel McAdams looks good in everything! From blonde to brunette to everything in between, there's no hair color she can't 'do.
Photo: Getty Images

Kylie Jenner has experimented with every hair color under the sun, including exchanging her naturally dark hair for a whole host of blonde shades. Photo: Getty Images

Reese Witherspoon has not only been Legally Blonde, she's been a dark brunette too!
Photo: Getty Images

Kristen Stewart can make everything look edgy. From brunette to blonde, she gives a rockstar vibe to both styles.
Photo: Getty Images

Miley Cyrus went full Hannah Montana by going blonde in real life. After years of being a brunette, she opted to experience the lighter side.
Photo: Getty Images

Scarlett Johansson wore a dark wig for 'Ghost in the Shell' and was red for 'The Avengers' and in real life she switches back and forth from super light to dirty blonde.
Photo: Getty Images

Jessica Alba went a few shades lighter from her naturally brown locks, still maintaining an overall caramel hue.
Photo: Getty Images