Margot Kidder, who was best known for her role as Lois Lane in the Superman film series, has died at the age of 69.

Kidder passed away on Sunday in her home in Livingston, Montana, her cause of death is still unknown.

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She began acting in the 1960s, but her claim to fame was her role as Lois Lane in the 1978 Superman. She starred alongside Christopher Reeve, and continued on with the role for the three sequels that followed.

Kidder also starred in The Amityville Horror as Kathy Lutz in 1979. She then appeared in other movies such as Black Christmas and Heartaches. She then began working as a producer for the 1983 adaption of Pygmalion, which she also starred in with Peter O’Toole.

However, Kidder also experienced her share of hardships following her fame and success. In the 1990s she was suffering from mental health issues that ultimately left her homeless. In 1996, she was missing for days when the police found her and took her to Olive View-UCLA Medical Center.

Kidder was Canadian-born, but became an American citizen in 2005 so she could vote.

She is survived by her only daughter, Maggie McGuane.

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After the news of her death broke out, many stars took a moment to share the impact Kidder made on them.