In his tribute to late actress Conchata Ferrell, Charlie Sheen said the star was a "genuine friend"

Charlie Sheen is mourning the death of his "genuine friend" and former Two and a Half Men costar Conchata Ferrell.

Following news of her passing, Sheen paid tribute to the late star on Twitter. "An absolute sweetheart," Sheen tweeted Tuesday alongside a photo of himself and Ferrell on the popular sitcom.

"A consummate pro," continued Sheen, 55. "A genuine friend. A shocking and painful loss."

"Berta, your housekeeping was a tad suspect," he joked, affectionately adding, "your 'people' keeping was perfect."

For years, Ferrell — who had been acting since 1974 — played Sheen's beloved housekeeper Berta on the CBS comedy series. Ferrell starred in the show from 2003 through the finale in 2015. She also starred in the TV series The Ranch, Grace and Frankie and The Wild Thornberrys.

Conchata Ferrell, Charlie Sheen
Conchata Ferrell, Charlie Sheen
| Credit: Donato Sardella/WireImage

Ferrell died Monday, Oct. 12 at age 77 due to complications following a cardiac arrest, Deadline reported. She was surrounded by family at Sherman Oaks Hospital in Sherman Oaks, California.

Ferrell's manager did not immediately respond to PEOPLE's request for comment.

Her husband, Arnie Anderson, told TMZ in July that the actress was hospitalized in May after feeling sick. Ferrell spent over four weeks in the intensive care unit and went into cardiac arrest at one point, which Anderson said lasted for about 10 minutes. Ferrell was then transferred to a long-term care facility and put on a respirator and dialysis, unable to speak or communicate.

Charlie Sheen, Conchata Ferrell
Charlie Sheen and Conchata Ferrell in Two and a Half Men
| Credit: Cliff Lipson/CBS Photo Archive via Getty

The actress explained to TMZ in February that she had been hospitalized for a kidney infection in December in Charleston, West Virginia, where she had been living at her vacation home since Thanksgiving.

The infection grew worse as it spread and began to contaminate her blood, she shared. Ferrell spent weeks in the ICU before being released and put into transitional care in January. She spent the month bedridden as she recovered at home, going through physical therapy several times a day.

The actress told the outlet her husband was by her side throughout the ordeal and worked tirelessly to care for her.