Superman actress Margot Kidder’s death was suicide, a coroner has said.

Kidder, who played Lois Lane in the film franchise of the late 1970s and early 1980s, died “as a result of a self-inflicted drug and alcohol overdose”.

She was found dead at her home in Livingston, Montana, on May 13. She was 69.

In a joint statement, Kidder’s family and the Park County Coroner’s Office said they are urging “those suffering from mental illnesses, addiction and/or suicidal thoughts to seek appropriate counselling and treatment”.

No further details will be released and the family has asked for privacy, the statement said.

Superman was a superhero blockbuster two decades before comic book movies became the norm at the top of the box office.

Both Kidder and co-star Christopher Reeve, who played Superman, were relative unknowns when they got their leading parts, and neither saw many major roles afterwards.

Reeve died in 2004. Following Kidder’s death, Reeve’s foundation paid tribute on Instagram.

Canadian-born Kidder also appeared in 1975’s The Great Waldo Pepper with Robert Redford and 1978’s The Amityville Horror.

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