03/24/2012 12:49 pm ET | Updated May 23, 2012

Alyson Hannigan's Style Evolution (PHOTOS)

Washington, D.C.-born actress Alyson Hannigan first won our hearts over back in the late '90's when she starred in the T.V. series in "Buffy the Vampire Slayer" and in the film "American Pie". An while her style may seem a bit out there, Hannigan charms us every time she steps in front of the camera.

To celebrate her 38th birthday on March 24th, we're taking a look back at the soon-to-be mother of two's most memorable looks, both on and off the red carpet. Click through the gallery below to see how Hannigan's style has evolved from midriff tops and tight jeans to ladylike dresses.