Kidder passed away in Montana on Sunday. The cause of death has yet to be revealed.
The Canadian star rose to fame as the love interest of Christopher Reeve in the four Superman films of the late ’70s and ’80s. Kidder made an early career in the horror genre starring in cult films like Sisters and Black Christmas, before playing opposite James Brolin in The Amityville Horror.
The actress – who suffered from bipolar disorder – made headlines in 1996 after being hospitalized for a manic episode in which she went missing for several days before turning up in the backyard of a home in Glendale, California.
In later years, she appeared on various TV shows like Law & Order:SVU, Brothers & Sisters, The L-Word and Smallville.
Kidder is survived by a daughter and two grandchildren.