With her recently announced pregnancy, today is bound to be a very happy 31st birthday for Kate Middleton. The entire world will be on baby-bump watch as she celebrates tonight, but as far as we can tell, Kate's amazing figure has yet to be affected by the pregnancy. Luckily for Kate, that means she can still have her pick of all the best looks from the Spring 2013 collections. We've taken the liberty of selecting some potential party dresses fit for the princess, straight from the S/S 13 runways.

[Photo: Prince William, Kate Middleton, Prince Harry via]

[All Slide Photos via Style.com]