Claim: Margot Kidder is a person who acts.

Margaret Ruth `` Margot '' Kidder -LRB- born October 17 , 1948 -RRB- is a Canadian American actress and activist . She rose to fame in 1978 for her role as Lois Lane in the Superman film series , opposite Christopher Reeve . Kidder began her career in the 1960s appearing in low-budget Canadian films and television series , before landing a lead role in Quackser Fortune Has a Cousin in the Bronx -LRB- 1970 -RRB- .   She then appeared playing Siamese twins in Brian De Palma 's cult thriller Sisters -LRB- 1973 -RRB- ; in the slasher film Black Christmas -LRB- 1974 -RRB- ; and the drama The Great Waldo Pepper -LRB- 1975 -RRB- , opposite Robert Redford . Her performance as Kathy Lutz in the blockbuster horror film The Amityville Horror -LRB- 1979 -RRB- gained her further mainstream exposure .   After a highly publicized manic episode and nervous breakdown in 1996 , Kidder 's career began to slow . By the 2000s , however , she had maintained steady work in independent films as well as television , with guest-starring roles on Smallville , Brothers & Sisters , and The L Word . In 2015 , she won an Emmy Award for her performance on the children 's television series R.L. Stine 's The Haunting Hour . She has also acted in theatrical productions , most notably appearing on Broadway in a 2002 production of The Vagina Monologues .   In 2005 , Kidder became a naturalized U.S. citizen . She is an outspoken political , environmental , and anti-war activist . She has also advocated the use of orthomolecular medicine , which she credits as having helped treat her bipolar disorder .