Ed Asner Speaks Out After 'Dear Friend' Valerie Harper's Death: 'Goodnight Beautiful'

Ed Asner is paying tribute to his late costar and “great friend,” Valerie Harper.

Following the sad news that Harper had died at the age of 80 following a long battle with cancer, Asner honored the actress in a touching statement obtained by PEOPLE.

“Valerie was a brilliant artist with a myriad of ideas on how to make the character more interesting; and was a fighter for those less fortunate,” said Asner, 89.

The actor also shared an emotional post on Twitter, where he called Harper “a beautiful woman, a wonderful actress, a great friend and with balls bigger than mine.”

RELATED: Valerie Harper Says She’s ‘Ready To Go’ and Has Made Peace With Her Cancer Diagnosis

“Her brilliance burst through and shined its light upon all of us,” he wrote alongside a smiling throwback photo of the Mary Tyler Moore Show costars holding Emmy Awards. (She starred as Rhoda Morgenstern and he as Lou Grant on the 1970s sitcom.)

“Goodnight beautiful. I’ll see you soon,” he concluded.

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, died Friday, PEOPLE confirmed.

The star died at 10:06 a.m., her family confirmed to ABC7. Her cause of death was not immediately known.

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

RELATED: From the Mary Tyler Moore Show to Broadway and Rhoda: Valerie Harper’s Life in Photos

In late July, Asner shared a tweet honoring Harper, just two days after the actress’ husband Tony Cacciotti revealed that doctors had advised her to be moved to hospice care.

“My heart goes out to @ValerieHarper and her husband Tony,” Asner wrote. “I hope you feel my love coming at you like a tidal wave.”

Harper was diagnosed with leptomeningeal carcinomatosis in 2013, just four years after she beat lung cancer. The condition occurs when cancer cells spread into the fluid-filled membrane surrounding the brain, known as the meninges.

At the time of her diagnosis, doctors told her she only had three months to live, but Harper beat the odds and continued to live well beyond their expectations by six years.