Which actress played Amy Farrah Fowler?

Mayim Bialik played Amy Farrah Fowler on The Big Bang Theory. She first appeared as Amy in the season-three finale, “The Lunar Excitation,” before becoming a recurring character and eventually a main cast member.

Amy is a neuroscientist whose research involves addiction and behavior in primates and other animals. In the story, an online dating profile matches her with Sheldon Cooper, beginning an unusual friendship that gradually develops into a romantic relationship. Their relationship becomes one of the show's major later storylines.

Mayim Bialik brought a scientific background to the role as well as acting experience. Before joining the sitcom, she earned a doctorate in neuroscience from UCLA. That real-life qualification often causes viewers to assume she was playing herself, but Amy is a fictional character with her own biography and research interests.

The other actresses listed had different roles: Melissa Rauch played microbiologist Bernadette Rostenkowski, Kaley Cuoco played Penny, and Sara Gilbert played Leslie Winkle.