Jeanne Cooper, star of CBS' 'The Young and the Restless,' dies at 84 LOS ANGELES (Reuters) - American actress Jeanne Cooper, who starred on the daytime television soap opera "The Young and the Restless" for four decades, died on Wednesday, her son, actor Corbin Bernsen, said. Cooper was 84. "My mother passed away this morning just a short time ago, peaceful with my sister by her side, in her sleep," Bernsen said in a post on Facebook. Bernsen had been updating the status of Cooper's health on Facebook and Twitter over the past few weeks. Neither the cause of Cooper's death nor what she had been suffering from has been disclosed. Cooper joined the cast of CBS network's "The Young and the Restless," in its first season in 1973, and portrayed the boozy and wealthy Katherine Chancellor. She was still a cast member at the time of her death although her character recently underwent surgery for a brain tumor. Known as the "The Duchess" and the "Grand Dame of Genoa City," the Chancellor character is credited with giving the series a dash of controversy during its beginnings and becoming an iconic figure in U.S. television soap opera genre. Cooper's cast mates took to Twitter to remember an enduring star of U.S. daytime television. "A very sad day for all of us," co-star Jessica Collins posted on Twitter. "Heaven just gained one feisty angel," said Melissa Claire Egan, another actress on the series. Cooper, a daytime Emmy winner, also brought her personal life onto the show in 1984 when footage of her real-life facelift was used to depict her character undergoing the same procedure. Cooper was born in Taft, California, in 1928 and began her professional screen acting career in the 1953 film "The Redhead from Wyoming." She also appeared on several television shows in the 1950s and 1960s, including "The Twilight Zone" and "Perry Mason," before joining "The Young and the Restless." Cooper had three children, Caren, Collin and Corbin, who currently stars on the comedy-drama series "Psych" on the USA Network. Reporting by Eric Kelsey; editing by Jill Serjeant and Jackie Frank