Danica Mae McKellar (born January 3, 1975) is an American actress, mathematics writer, and education advocate. She played Kevin Arnold's on-off girlfriend Winnie Cooper in the television series The Wonder Years.From 2010-2013 and 2018-present, McKellar voiced Miss Martian in the animated superhero series Young Justice. In 2015, McKellar was cast in the Netflix original series Project Mc2. She also appears in several television films for Hallmark Channel...