Kate McKinnon. Actress: Ghostbusters. Kathryn McKinnon Berthold (born January 6, 1984), known professionally as Kate McKinnon, is an American actress and comedienne, who is best known as a regular cast member on Saturday Night Live and The Big Gay Sketch Show, and for playing the role of Dr. Jillian Holtzmann in the 2016 Ghostbusters reboot. McKinnon is known for her character work and celebrity impressions of pop singer Justin Bieber, comedian...