Jennifer Aniston hits the big 4-0 this year! Yes, that's right. America's Sweetheart turned forty today. And all we have to say is, "Wow!" She's come a long way.

Looking back on her style evolution throughout the years, we think Jennifer is better now than she ever was before. After her divorce and subsequently going from tabloid victim to the happy girl next door again, she looks more confident, beautiful and content in her life. While last year was the year of the naked GQ spread, there were even rumors that Playboy wanted her to pose for them this year. If that's not success at 40, we don't know what is!

Jennifer has made a month long celebration out of her birthday -- we've already seen her talking about how great she feels and eating cake with Ellen, plus she threw a star-studded birthday bash last weekend for all her A-list friends.

And, rumor has it that she may be receiving one of the most special gifts ever -- a song written about her by John Mayer. Look how sweet 40 can be!