Superman Star Margot Kidder Dead At 69

Actress Margot Kidder

Best known for her portrayal of strong-willed reporter "Lois Lane" in the 1978 hit film Superman: The Movie, actress Margot Kidder has died at the age of 69.

People Magazine reports Kidder passed away on Sunday at her home in Livingston, Montana, of unknown causes.

Although she began her career in the 1960s, Kidder saw her star skyrocket after her turn as "Lois Lane" in Superman: The Movie opposite Christopher Reeve. She would go on to reprise the part of the intrepid Ms. Lane in three film sequels.

Other credits include 1974's Black Christmas, 1979's The Amityville Horror and Heartaches in 1981.

She also served as producer and starred as Eliza Doolittle in a 1983 adaptation of Pygmalion opposite Peter O’Toole for Showtime.

However, amid all that success, Kidder quietly waged war with mental health demons that eventually left her homeless.

From People:

After being reported missing for days in 1996, police took her away in handcuffs to Olive View-UCLA Medical Center.

“The woman we saw was in obvious mental distress,” Officer Rick Young of the Glendale police told PEOPLE at the time. “She didn’t think one person was following her. She thought a whole group of people were after her.”

Kidder told PEOPLE five months later that the root of most of her problems — which include “mood swings that could knock over a building” — was manic depression. She was first diagnosed with the condition by an L.A. psychiatrist eight years prior, but she refused to take the recommended prescription of lithium, the recommended treatment.

“It’s very hard to convince a manic person that there is anything wrong with them,” said Kidder, who was working on a memoir at the time. “You have no desire to sleep. You are full of ideas.”

She is survived by her daughter.

Watch the famous flying sequence from Superman: The Movie below: