Reese Witherspoon
Credit: Pat/Garcia/Stills/Retna; Vince Bucci/NBC/NBCU

What a week for Reese Witherspoon! Not only did is she pregnant with baby number three, the Oscar winner is also celebrating a birthday! The actress turns 36 today, and in celebration, we're taking a look back at her best beauty looks throughout the years. See her transformation now in the gallery now.