PIC: See Carey Mulligan With Long Brown Hair!

Credit: Dave M. Benett/Getty Images; JT/Donnelly/INFphoto.com

This blonde is now back to being a brunette - temporarily!

On the set of her upcoming flick Inside Llewyn Davis in NYC Friday, Carey Mulligan has traded her iconic blonde pixie cut for long brown locks.

The last time the actress, 26, went to the dark side was in May 2011, just months before getting engaged to her beau, Mumford & Sons singer Marcus Mumford in August.

Prior to that, the star (whose natural hair color is brown) went through a dramatic hair change for a movie. In 2009, she bleached her hair platinum blonde for Public Enemies -- a change which she opened up to Elle UK about.

"I hate my hair. After An Education, I had a small part in Michael Mann's film Public Enemies and he wanted me to dye it white blonde, and it wrecked my hair," Mulligan told the mag. "Literally, ruined it. It was falling apart, fried. So I had to cut it off. I cried."

VOTE: What's her best hair color?

For Wall Street: Money Never Sleeps and Never Let Me Go, where she starred opposite then-boyfriend Shia LeBeouf and Andrea Garfield, respectively, she continued to maintain her sunny locks.