Susan Alexandra "Sigourney" Weaver (born October 8, 1949) is an American actress. She is best known for her roles as Warrant Officer (later Lieutenant) Ellen Ripley in Ridley Scott's Alien (1979), James Cameron's Aliens (1986) and in the rest of the Alien film series, as Dana Barrett in the Ghostbusters films, as Jill Bryant in The Year of Living Dangerously (1983), as Helen Hudson in Copycat (1995), as Max Conners in Heartbreakers (2001), as Warden Walker in Holes (2003), and as Dr. Grace Augustine in Avatar (2009), the highest-grossing film in history.
Weaver is also a three-time Academy Award nominee for her performances in Aliens (1986), Gorillas in the Mist (1988), and Working Girl (1988).