Margot Kidder, the Canadian actress who starred as Lois Lane in the Superman film franchise of the 1970s and 1980s, has died aged 69.

Kidder died on Sunday at her home in Livingston, Montana, according to a notice on the website of Franzen-Davis Funeral Home.

Kidder's manager Camilla Fluxman Pines said she died peacefully in her sleep and no cause or details were given.

Superman, directed by Richard Donner and released in 1978, was a superhero blockbuster two decades before comic book movies became the norm at the top of the box office. It is cited as an essential inspiration by makers of modern day Marvel and DC films.

Kidder had many of the movies' most memorable lines, including "You've got me?! Who's got you?!" when she first encountered Superman as she plunged from the top of a Metropolis building.

Kidder and Reeve were relative unknowns when they got their leading parts in the first of the films in 1978, which also included big names Gene Hackman and Marlon Brando.

They went on to star in three more Superman movies - and were said to be like brother and sister, both in their affection and animosity for each other.

"We quarrelled all the time," Kidder said on May 9 in an interview on radio station WWJ in Detroit.

"The crew would be embarrassed. They would look away.

"Then we'd play chess or something because we were also really good friends."

Both would remain known almost entirely for their Superman roles, and struggled to find other major parts.

Kidder also had a small part in 1975's The Great Waldo Pepper with Robert Redford, and starred as conjoined twins in Brian De Palma's 1973 Sisters, and as the mother of a terrorised family opposite James Brolin in 1979's The Amityville Horror.

She appeared small films and television shows and amassing credits until 2017, most notably R.L. Stine's The Haunting Hour, which earned her a Daytime Emmy Award as outstanding performer in a children's series in 2015.

"I don't act much anymore unless I'm broke, and then I'll take a job," she told the Detroit radio station with a laugh.

She spent the last decades of her life living in Montana and engaging in political activism, including protest against the US military action in Iraq.