Marcia Wallace, whom many know best as the voice of Mrs. Edna Krabappel on the long-running Fox animated series 'The Simpsons,' has passed away at the age of 70. Wallace, who was also starred on the classic sitcom 'The Bob Newhart Show,' died just one week before her 71st birthday due to complications from breast cancer.

Marcia Wallace got her start in Hollywood with guest appearances on 'Bewitched' and 'The Brady Bunch.' From 1972 to 1978, she portrayed Carol Kester Bondurant on 'The Bob Newhart Show' with Bob Newhart. She also appeared on the short-lived Comedy Central series 'That's My Bush!' and had a recurring role on 'The Young and the Restless,' highlighting her diversity as an actress.

But fans will remember her best as the voice of Edna Krabappel, Bart Simpson's feisty, no-nonsense teacher on 'The Simpsons.' Wallace voiced the beloved character since 1990, providing us with 23 years of her trademark, sarcastic "Ha!"

Though it was recently announced that a character that is played by an actor/actress who won an Emmy for the role would be dying on the show, Wallace's passing has nothing to do with that creative decision.

According to Deadline, Wallace passed away last night due to complications from breast cancer, confirmed by friend Cathryn Michon, who recently directed Wallace in the upcoming film 'Muffin Top: A Love Story.' The film will be Wallace's final performance, appearing alongside her son, Michael Hawley.