Emily Blunt's new blonde hairEmily Blunt has given up her sexy, dark chocolate hair to lighten up her 'do.

The 27-year-old British beauty debuted much lighter locks at the premiere of her new film, 'Gnomeo & Juliet' in Hollywood.

So why is Blunt messing with a good thing? Apparently for a new role.

The 'Devil Wears Prada' star has been gradually lightening her tresses in preparation for the upcoming time-travel thriller 'Looper', where she plays a mother protecting her son.

Blunt has reportedly been having weekly sessions with colorist Anival Morales at the Essensuals London Salon in Los Angeles to take her from a sultry brunette to a strawberry blonde.