Margot Kidder rose to fame when she played Lois Lane, playing opposite Christopher Reeve in the 1978 Superman film that captured imaginations across the globe.
Tragically, she passed away on Sunday.
Margot was 69 years old.
TMZ reports that Margot Kidder passed away at home in Montana.
That much is known thanks to a statement from the spokesperson at Franzen-Davis Funeral Home in Livingston, Montana.
Her cause of death, however, has yet to be reported.
After three marriages, Kidder had remained single since the 1980s.
She is survived by her only daughter, Maggie McGuane, and by two grandchildren.
Canadian by birth, Margot Kidder took on a number of smaller acting roles before being catapulted to fame in the 1978 Superman film.
She would then go on to reprise her role of Lois Lane in the ensuing sequels.
She also took on other film roles, most notably in horror films like Amityville Horror and Black Christmas.
After a car crash in 1990, she was unable to work for years, which resulted in financial problems.
Nonetheless, her film legacy lives on, and she is mourned by countless fans.
Additionally, she continued working up until this very year. TMZ notes that two of her roles have yet to be aired.
She had bipolar disorder.
In April of 1996, Kidder suffered a particularly severe manic episode, following the crushing disappointment of having years of work on her memoir undone by a virus.
She disappeared for four days, and was ultimately found by a neighbor.
Following that incident, she became an outspoken activist for mental health awareness and treatments.
Kidder was an outspoken anti-war activist and advocate for environmental responsibility.
She was naturalized as a US citizen in 2005 and moved to Montana, though she continued to fly out to L.A. and other locations for acting work.
No matter which actress you believes did the best portrayal of Lois Lane -- for there have been a number of them -- it was Kidder who paved the way for the role in the iconic movie.
We do not know when her cause of death will be revealed.
In the mean time, our thoughts are with her daughter, grandchildren, and other loved ones as they mourn this tragic loss.
Kidder was a rare talent and she is sorely missed.