Kidder was best known for playing Lois Lane
Canadian born "Superman" actress Margot Kidder has died at age 69.
Best known for playing Lois Lane opposite Christopher Reeve in the "Superman" films of the 1970s and 1980s, she went on to become an advocate for mental health issues after speaking out about living with bipolar disorder.
She also became a political activist in recent years and was among a group of environmentalists to be arrested outside the White House in 2011 during a protest against TransCanada's Keystone XL pipeline.
Kidder, who became an American citizen, had settled in Montana to live in a "culture-free zone" away from the spotlight and close to her daughter and grandchildren.
— with files from The Canadian Press