Marcia Wallace, who gained fame on The Bob Newhart Show and whom audiences embraced as teacher Edna Krabappel on The Simpsons, has died. She was 70.

"I was tremendously saddened to learn this morning of the passing of the brilliant and gracious Marcia Wallace," said Simpsons executive producer Al Jean in a statement to Entertainment Weekly. "She was beloved by all at The Simpsons, and we intend to retire her irreplaceable character."

The actress' popularity spanned generations. She appeared on The Merv Griffin Show over 75 times and earned fame playing Carol Kester, the clever, sarcastic secretary on The Bob Newhart Show. She later nabbed an Emmy nomination for a turn on Murphy Brown as 'Secretary 66' in 1994.

Wallace won an Emmy for voicing Bart Simpson's dry teacher on the Fox animated series. As THR notes, the 1992 Simpsons episode for which she won found Ms. Krabappel giving Bart a month of detention. He exacted revenge by responding to her newspaper singles ad. Wallace would go on to star in 177 episodes of The Simpsons, her character's iconic "Ha!" a familiar echo.

Wallace's friend Cathryn Michon, who co-wrote and directed Wallace's last film, the upcoming Muffin Top, told Deadline that the actress passed away at 9 p.m. Friday night "due to complications from breast cancer of which she was a long and proud survivor and advocate for women and healing." Wallace was first diagnosed with breast cancer in 1985. "Ironically (her death) was during breast cancer awareness month, during which she was always a funny ray of hope for so many," said Michon.

Just before a Bob Newhart Show reunion in 2007, co-star Suzanne Pleshette told USA TODAY she and Wallace had bonded over both surviving cancer. "We've been able to be completely open with each other, which I don't even do with my other girlfriends," said Pleshette.

In 2004, Wallace published an autobiography, Don't Look Back, We're Not Going That Way. The comedian aired out the book's contents in the subtitle, which read How I Overcame a Rocky Childhood, a Nervous Breakdown, Breast Cancer, Widowhood, Fat, Fire & Menopausal Motherhood and Still Managed to Count My Lucky Chickens.

The actress was also a common fixture on game shows, including Hollywood Squares, The $25,000 Pyramid, To Tell the Truth and Match Game. Wallace's husband of six years, hotelier Dennis Hawley, died in 1992. Their son, Michael Hawley, recently appeared with her in Muffin Top.

Upon news of Wallace's death, a video of Ms. Krabappel's memorable "Ha!" moments began to circulate on Twitter.