See the actress's transformation through the years.
2001
"Not an attractive shade," Blunt told InStyle of her blond strands. "It's a combination of lemon juice and Sun-In. I was 18."
2004
The star of My Summer of Love wore her layered locks in loose waves.
2006
For The Devil Wears Prada, Blunt went auburn.
2007
At the Academy Awards, she pulled her hair back into a sophisticated ponytail.
2007
"Red was fun for The Devil Wears Prada, but I'm more comfortable dark or blonde," the actress said of her Crystal and Lucy Awards hue.
2009
For the Screen Actors Guild Awards, the Young Victoria actress pulled her still-dark locks back into a chignon.
2010
Blunt borrowed from the birds for the premiere of The Wolfman. "We used eye shadow shades that matched the feathers in her headband," said makeup artist Jenn Streicher.
2010
At Fair Game cocktail party hosted by Giorgio Armani in Cannes, Blunt wore Streicher's favorite lip hue. "I have been obsessing about the color and wearing it a lot myself," the makeup artist told us. "It's a great spring color - it's pink, but a young, fresh version that's flattering on almost everyone."
2010
"Her fashion sense has a strong British influence," hairstylist Laini Reeves said of Blunt's sleek style. "We sewed a vintage necklace onto an elastic headband for this event."
2010
The newlywed supported husband John Krasinski at the Emmy Awards. "We wanted a style that was very different from any that Emily had worn before," said Reeves. "I knew that a modern look based on '20s waves was the perfect complement to her gown." By adding the finishing touch - a diamond earring sewn along two criss-crossed bobby pins - Reeves made sure the retro updo had a one-of-a-kind vibe.
2011
Blunt played up her auburn hue with geranium-tinted balm and bronze shadow.
2011
At the U.K. premiere of Gnomeo and Juliet 3D, the actress sported a honey-hued shoulder-length bob.
2011
For the Emmys, Blunt wore a romantic updo with face-framing tendrils.
2011
"This is my new cut and color. It's the darkest and most drastic I've ever done," Blunt told InStyle of her dark bob. "I had mid-length long hair for so long, so I fancied a change."
2012
At the premiere of Salmon Fishing in the Yemen, Blunt paired a retro-inspired cat eye with a petal pink lip. "I was very inspired by Emily's dress, and drew upon its chic '50s-esque silhouette for her look," said Streicher.
2012
Blunt lightened up for her role in All You Need Is Kill. "I just did it today and it's the craziest haircut I've had," the actress told us of her sun-kissed look when she stopped by InStyle's pop-up portrait studio at the Toronto International Film Festival.
2012
For the N.Y.C. Gotham Awards, Blunt chose sheer, shimmery shades. "I was going for a pretty and feminine look with everything from my Calvin Klein Collection dress, to my makeup's golden hue," she told us. "I felt beautiful!"
2013
"Emily wanted smoky eyes paired with soft pink lips that echoed her Lorraine Schwartz ruby earrings," said the star's makeup artist Jenn Streicher of her Golden Globes look. After creating a smooth canvas, she defined Blunt's eyes with Hourglass's Kohl Eye Pencil in Espresso and smudged the line with a shadow brush. Picking up a pale shimmer shade from the Hourglass Shadow Duo in Gypsy, she highlighted the brow bone and blended the matte brown onto her lids.
2014
Blunt was back to a deep brunette shade, pulling her locks up into a soft updo for the Into The Woods premiere.
2015
This hair color chameleon never tires of change! The actress was a blonde bombshell during Paris Fashion Week with retro waves.
2016
Blunt arrived at the Girl on the Train looking nothing like her haggard character. The then 33-year-old looked gorgeous with a sleek blonde bun and soft pink lip.
2017
For the SAG Awards, the actress dyed her hair a sandy blonde, styling her locks straight in a side part.