Cameron Diaz is known to the world as a bubbly California blonde. But for a brief moment not too long ago, she took a turn as a chocolate brunette. The results were stunning. She looked so exotic, mysterious and beautiful, we wonder why she went back to blonde.

Once just another highlighted Hollywood teen queen, Hilary Duff grew up and took her own hair color tour of duty, trying just about everything from her usual blonde to this stark dark brown. Sometimes you have to hit bottom before admitting you have a problem. This harsh shade is all wrong for Duff's skin tone, unless she's hoping to land a role as a vampire.

Ashlee Simpson-Wentz may fake a few things, like her hair color. But when she does, she does it well. This glossy chocolate shade, paired with a sassy shag haircut, may have been her finest hour. This look inspired imitators everywhere and continues to do so today.

Brittany Snow is another blonde who reached new heights of beauty by going brunette. This is one dramatic makeover, taking Snow from cutesy to couture. Once again, we're left to wonder why she would ever go back to blonde.

Yeah, yeah. We know. It was for her "Fantastic Four" character. Still, it's a great example of someone who just wasn't born to be blonde. Jessica Alba's super-brassy blonde is not just unflattering on her. It's a bad hair color period. If you're a lovely latina like Jessica, work with your natural assets. You won't go wrong. The world has enough blondes.