She's also known for playing the geeky witch Willow Rosenberg on Buffy The Vampire Slayer and the band geekette Michelle in the American Pie movies. She is married to actor Alexis Denisof who is recurring guest star on HIMYM, playing Sandy Rivers. Their first daughter is named Satyana Marie Denisof, born on March 24, 2009. In December 2011, it was reported that Hannigan was pregnant with her second child. Her second daughter, Keeva Jane Denisof, was born on May 23, 2012.