Mary Willa "Mamie" Gummer (born August 3, 1983) is an American actress. She starred in the title role of the CW series Emily Owens, M.D. (2012–13), and plays the recurring role of Nancy Crozier on The Good Wife (2010–15). She has also appeared in the films Evening (2007), Side Effects (2013), Cake (2014), and Ricki and the Flash (2015).