Duke's agent told the Associated Press  that the actress died early Tuesday morning of sepsis from a ruptured intestine.

In addition to being a stage, film and television actress, Duke was a mental health advocate.  She was diagnosed with bipolar disorder in 1982.

Duke won an Academy Award for Best Supporting Actress for her role in "The Miracle Worker."

Two of her three children, Sean Astin and Mackenzie Astin, are also actors.

A statement from the family has been posted on social media.

Fans took to social media to pay their respects.