Marcia Wallace, the voice of Edna Krabappel -- Bart Simpson's jaded, chain-smoking schoolteacher on the animated show "The Simpsons" -- has died, the show producers said Saturday. She was 70.

Wallace died in Los Angeles of complications from pneumonia, her son Michael Hawley told the Los Angeles Times.

Wallace's career in show business included her role as a sassy receptionist on the 1970s TV comedy "The Bob Newhart Show," and guest roles in '80s and '90s shows like "Full House," "Taxi" and "Murphy Brown."

As Mrs. Krabappel, Bart's fourth-grade teacher since 1990, Wallace was best known for her animated character's sarcastic cackle.

"I was tremendously saddened to learn this morning of the passing of the brilliant and gracious Marcia Wallace," read a statement from the show's executive producer Al Jean posted on Facebook.

"She was beloved by all at 'The Simpsons' and we intend to retire her irreplaceable character," Jean wrote.

In 1992 Wallace won a Primetime Emmy award for her role as Mrs. Krabappel in a "Simpsons" episode titled "Bart the Lover."

In the episode Bart takes revenge on his divorced teacher for receiving a month of detention by posing as a handsome adult man and answering her love-lorn personal newspaper ads.

Harry Shearer -- who plays several key "Simpsons" voices, including greedy tycoon Montgomery Burns and two of Krabappel's love interests, school principal Seymour Skinner and Simpsons neighbor Ned Flanders -- took to Twitter to share his grief.

"So sad to learn -- through Twitter, first -- of the passing of the wonderful Marcia Wallace. Sorely missed already," Shearer wrote.

Jean said the show had been considering staging the death of another one of the "Simpsons" characters, but not Edna Krabappel.

"Marcia's passing is unrelated and again, a terrible loss for all who had the pleasure of knowing her," Jean wrote on Facebook.

Wallace was "sweet, funny, not at all pretentious," Jean told the Los Angeles Times. "You fall in love with these people when you see them as characters on television, but when you met Marcia you loved her even more."

"I don't intend to have anyone else play Mrs. Krabappel," Jean added. "I think Bart will get a new teacher."

Her 2004 autobiography is titled "Don't Look Back, We're Not Going That Way (. . . or how I overcame a rocky childhood, a nervous breakdown, breast cancer, widowhood, fat, fire and menopausal motherhood and still managed to count my lucky chickens)."

Born and raised in Creston, Iowa, Wallace traveled to New York after graduating from college in 1964 looking for an acting job.

"I weigh 230 pounds (104 kilos) and have $150 in the bank.... I supposed my ready cash should at least equal my weight, but what the hell, I've always had more guts than brains," she wrote in a letter to a friend that appears in the book.

Wallace's final role is in "Muffin Top: A Love Story," a film set for release in 2014 in which she appears with her son, who is also an actor.