By Molly McGonigle

The entertainment industry is a lot like high school: Having the best smile makes you more popular and more likely to succeed. Click through to count down the best grins in Hollywood.

15. Ellen DeGeneres

She's a successful comedian with a beautiful wife at home -- no wonder Ellen DeGeneres is always smiling. And that easy, breezy, beautiful grin is most likely what landed her the coveted role of a CoverGirl a few years ago.