Actress Margot Kidder passed away on Sunday, according to a report from TMZ. She is survived by her daughter Maggie McGuane.

Kidder played Lois Lane in the original Superman: The Movie released in 1978, starring alongside Christopher Reeve, and its subsequent sequels.

The report states that Kidder passed away at her home in Montana at the age of 69, though the cause of death is still unknown.

Though Kidder is recognized for her role as Lois Lane in the original Superman series of films, she had a prosperous acting career.

She starred as Kathy Lutz in the successful horror film The Amityville Horror. She also appeared alongside Reeve in the small-screen Superman adaptation Smallville as Bridgette Crosby.

Kidder appeared on Broadway in a production of The Vagina Monologues in 2002, and has had roles on television series such as The L Word and Law & Order: Special Victims Unit.

The actress won an Emmy award in 2015 for Outstanding Performer in Children’s Programming for her role in R.L. Stine’s The Haunting Hour.

Kidder has been open about her struggles with bipolar disorder and became an advocate for mental health. She spoke about her recent routines with Hey U Guys in 2016 while discussing the possibilities of appearing in DC Comics-based TV shows.

"I am an old broad now!" Kidder said. "So I look back at this with much more amusement than I did. I don’t have a career I need to worry about protecting. My life has nothing to do with movies anymore. I live in a little town in Montana and basically do political activism."

Kidder was born on October 17, 1948, in the Yellowknife, Northwest Territories, Canada. She became a naturalized U.S. citizen in 2005.

Our thoughts go out to Kidder's friends and family at this time.

[h/t TMZ]