Valerie Harper, who played one of TV’s most popular and enduring characters — the constantly dating, constantly dieting Rhoda Morgenstern — for nearly a decade starting in 1970, has died, PEOPLE confirms. She was 80.

Harper’s daughter Cristina Harper Cacciotti spoke out about her mother’s death on behalf of her father Tony Cacciotti on Twitter writing, “My dad has asked me to pass on this message: ‘My beautiful caring wife of nearly 40 years has passed away at 10:06 a.m., after years of fighting cancer.’”

“She will never, ever be forgotten. Rest in Peace, mia Valeria. — Anthony.”

Harper had been battling a number of health issues over the past few years, including leptomeningeal carcinomatosis, lung cancer and brain cancer.

On July 8, a family friend set up a GoFundMe page titled “The Valerie Harper Cancer Support Fund” in order to assist Harper with her daily “unrelenting medical costs” so that she would receive “the best care possible.”

Within the first week, the campaign had raised over $40,000 from friends, family and many of Harper’s beloved fans.

Once she debuted as the kooky neighbor from New York on The Mary Tyler Moore Show in 1970, Harper liked to say, “People identify with Rhoda because she’s a loser” — a claim that the actress would soon have to deny.

Though the CBS Saturday night sitcom was not a ratings hit its first season, Harper took home the Emmy for Best Supporting Actress. After that, the show remained solidly in the top 10 for years, and Harper won two more supporting actress awards.

From that success came the 1974–78 spin-off Rhoda and a Best Actress Emmy. When Rhoda got married, on October 28, 1974, the special hour-long episode shattered ratings records with 52 million viewers — more than half of America’s entire viewing audience.

Valerie Harper was born in Rockland County, New York in the town of Suffern to parents Iva and Donald. Her mom was a nurse, while her dad was a lighting salesman who traveled the country, taking his family with him. By the age of 13, Harper had lived in New Jersey, California, Michigan and Oregon.

Simultaneously taking ballet and attending Manhattan’s School for Young Professionals, Harper debuted professionally at age 16 as part of the Corps de Ballet at Radio City Music Hall, where, at 5 ft., 6 in., she said that she felt “like a klutz next to those other skinny girls.”

Hoping to graduate from the chorus, where she danced in such Broadway shows as 1960’s Lucille Ball musical Wildcat, Harper seriously plunged into acting lessons, though it was her comedic skills that got her into Chicago’s Second City Theater.

Some Broadway acting roles did follow, but then TV came to call. With few small-screen credits — and looking “rather chunky and unprepossessing,” according to The New York Times — in spring 1970, she auditioned among dozens of others to play the Jewish girlfriend of Mary Tyler Moore‘s divorced character on a new sitcom.

In the end, CBS didn’t think American audiences would accept Mary’s being divorced, but Rhoda could be Jewish (in real life, Harper called herself a lapsed Catholic).

“She croaked out one line and we knew we had what we’d been looking for,” James L. Brooks, who helped create The Mary Tyler Moore Show, told The Times about Valerie’s audition.

Once Rhoda debuted in 1974, PEOPLE reported: “After playing Rhoda on The Mary Tyler Moore Show for four seasons and winning three back-to-back Emmys, Valerie was rewarded with her own series this fall at $25,000 per episode (plus a percentage flyer). So far Rhoda is the top-ranked new show of the year.”

Although the show’s popularity started to wane after Rhoda got married (and divorced), Harper kept working, on stage, in movies and on TV.

In 1986, NBC presented her on the family sitcom Valerie, also starring a very young Jason Bateman, though after two years the network fired her and the case went to court. Harper sued for wrongful dismissal, and NBC countersued her for libel. The star ended up winning some damages, while NBC renamed the sitcom The Hogan Family.

While still with Second City, Harper met actor Richard Schaal. They were married from 1964 until their divorce in 1978. In 1987, she married her former fitness adviser, Tony Cacciotti.

When they first met, Harper told PEOPLE in 1980, “I thought, ‘What a beautiful, giving teacher.’ Although I’m a feminist and think it’s terrific to call a man if you’re comfortable, I don’t do it. I don’t set my cap for a guy unless he makes the first move.”

They were together until the end and had a daughter, Christina. In 2000, when their daughter was 16, Harper told PEOPLE that the two “have a great relationship so far” — while her husband pointed out that Harper could be a mom even to strangers.

“She talks to everyone at the supermarket,” said Cacciotti, “listens to their problems and tries to solve them.”

Added Mary Tyler Moore: “It doesn’t matter if a guy is yelling out of his truck, ‘Hey, Rhoda!’ She’ll ask him his name, does he have a wife, does he have any children?”
In March 2013, Harper announced” that she had leptomeningeal carcinomatosis, a rare condition that occurs when cancer cells spread into the fluid-filled membrane surrounding the brain. Her doctors said at the time that she had as little as three months left.

“I don’t think of dying,” the actress told PEOPLE in March 2013. “I think of being here now.”

In 2014, Harper told PEOPLE she was at peace with her diagnosis.

“I’m ready. I’m ready to go,” she said. “Maybe that’s the secret. That I’m absolutely — I don’t want to, my God, I want to live to be 102. … But I am not banking on anything, really, because we shouldn’t. We don’t know what’s around the corner. I think you just take each day and get the best out of it and do what you can and have fun.”

While she was diagnosed early with (and successfully treated for) lung cancer in 2009, Harper was later forced to cancel the February 2013 promotional plans for her memoir, just-published at the time, I, Rhoda, when she received her terminal brain cancer diagnosis in 2013.

“The side of my face started to feel kind of numb. I was slurring my speech,” she told The New Yorker in a phone interview at the time. The magazine reported that her “spirits were good.”

That, like it or not, was her Rhoda side coming out. Or, as the world was to learn, her Valerie Harper side.