(Yahoo!) - Then: Kate Upton was focused on getting glam for the camera from an early age. "I remember the days I had to do my own hair before a swimsuit shoot. #tbt," she joked of this early '90s pic she posted on Instagram.

Now: Upton, 21, is trying out acting in movies like the recently released "The Other Woman," but she's best known for modeling in barely-there bikinis (or less). As cover girl for the Sports Illustrated Swimsuit Issue in 2012 and 2013 — she also graced the back cover of the magazine in 2014 — Kate can leave her locks to the professionals now.