The similarities between these two fair-haired songbirds is striking (beyond boy-toy choices). Whether you're on Team Jess or Team Carrie (or you're cheering for both), it's clear they're both style icons in their own right. But which diva takes the crown in a direct faceoff? Let's find out ...

This sixties inspired updo is clean, classy and chic. Simpson paired it with a ladylike lace shift and elegant diamond studs in the ears, completing a look even Jackie O' could love.

While Underwood's updo is basically flattering, the backcombing work at the crown borders on beehive and looks unprofessional. The side wisps are pretty but don't jive with the hive. Updo Winner: Simpson.

The American Idol's side pony is graceful, flattering and looks touchable. It's a great easy formal hairstyle.

While Simpson's style is unique and fun, it's a little too styled for what should be a casual evening look. For a concept that is intended to say, "devil-may-care" it screams, "this took a lot of work!" Evening Pony Winner: Underwood.