Margot Kidder, the actress most famous for a decade spent playing the iconic Lois Lane in Christopher Reeves’s Superman films, died on Sunday at the age of 69. Her representative, Camilla Fluxman Pines, confirmed the news and said that Kidder was at home in Montana at the time of her death, but the cause was not disclosed. Born in the Northwest Territories in Canada, Kidder started her career in Hollywood with television roles in the late 1960s. She assumed the part of Lane in 1978. During that decade she also starred in two classic horror films, The Amityville Horror and Black Christmas, and played opposite legends like Robert Redford, Richard Pryor, and Christopher Walken. Kidder also battled mental illness throughout her life, and after suffering a highly publicized breakdown in 1996, became a passionate and dedicated advocate for mental-health awareness and destigmatization. She continued to act in films and television throughout her life.