The 29-year-old actress was spotted on the set of her latest movie, "Take This Waltz," in Toronto, Canada with a new copper-toned bob.
Dressed down and makeup-free, Williams looked happy in her fiery hairdo as she took a break from filming the dramedy about a woman struggling to choose between two different types of love.
But Williams isn't the only star to dye her strands red. She joins a cohort of newly redheads including Nicolas Cage, Snooki, Rihanna, Eva Longoria Parker, and Kristen Stewart.
And while the shade definitely warms up her milky complexion, we must admit that we loved the platinum blonde pixie haircut she debuted at the 2010 Cannes Film Festival.
What do you think about Michelle Williams' new hair color? Do you prefer her as a blonde?
Leave a comment below and click here to find out how many hairstyles the average woman tries over a lifetime.