Mayim Bialik as Amy Farrah Fowler - Then:
Mayim Bialik joined the cast as Amy in Season 3 of "The Big Bang Theory" when the guys set up a dating profile for Sheldon. Her limited social skills made her an ideal match for Sheldon, and her character, Amy, is a neurobiologist, a field that Mayim Bialik herself holds a real-life Ph.D. The show slowly developed Amy and Sheldon's relationship over the seasons.
