Jennifer Aniston Goes Brunette!

Credit: New Line Cinema

Jennifer Aniston has gone to the dark side.

The blonde, blue-eyed girl next door went brunette for her new, buzzed-about role in upcoming comedy Horrible Bosses.

Costarring Colin Farrell, Kevin Spacey and Jason Bateman, Horrible Bosses is more than a hair-color switchup for Aniston, 42: She plays a dentist who sexually harasses a male employee (Charlie Day) -- and, according to one source, Aniston bares her breasts in at least one scene. ("She shot a topless scene, but producers aren't sure if they'll use it," the insider told Us Weekly recently.)

Regardless, don't expect to see a brunette Aniston out and about. Her longtime colorist Michael Canale recently told Us the single star would make a dramatic color change "only for movie roles."

Canale would know: He has worked with Aniston for 15 years. "I began by taking her from a medium brown to a light golden brown with two bright highlights to accent the 'Rachel' cut," said Canale, who touches up the star's locks once about every five weeks. "From that point on we gradually went blonder."

Tell Us: Do you like Aniston as a brunette?