Los Angeles - Actress Margot Kidder, best known for playing Lois Lane in the "Superman" films in the 1970s and 1980s, has died at the age of 69, a funeral home in Montana said on Monday.
The Franzen-Davis Funeral Home in Livingston, Montana said on its website that Kidder passed away on Sunday at her home in the town. The cause of death was not immediately known.
Canadian-born Kidder also appeared in the movie "The Great Waldo Pepper" and the 2014 children's TV series "R.L. Stine's The Haunting Hour," for which she won an Emmy award.
Kidder shot to fame playing the intrepid reporter Lois Lane in 1987's "Superman," opposite Christopher Reeve and reprised the role twice more in "Superman II" (1980) and "Superman III" (1983).
In the mid-1990s, she suffered a mental health breakdown and, in a highly publicized episode, she disappeared for four days. She was later diagnosed with bipolar disorder.
Acting work dried up for several years, but Kidder later re-emerged with a guest starring role in TV shows like "Smallville" and "The L Word" and on stage including a 2002 Broadway production of "The Vagina Monologues."
She also was a prominent political activist, campaigning against the Gulf War, energy fracking and in support of Democrat Bernie Sanders in the 2016 U.S. presidential election.
Kidder became an American citizen in 2005.
She was married three times, including a six-day union in 1979 with actor John Heard.