Soap actress Jeanne Cooper on "The Young And The Restless" has died at age 84.  After a battle with an unknown illness, Cooper died peacefully in her sleep on Wednesday.

Jeanne Cooper was best know for playing Katherine Chancellor on "Young And The Restless" for four decades. 

"Jeanne was the matriarch of the show in every sense of the word," said Lauralee Bell, Christine/Cricket on "The Young and the Restless"

Ms. Cooper was the longest-serving cast member of "The Young and the Restless," having joined the show in late 1973, about six months after CBS began broadcasting. As Katherine Chancellor, she played the fabulously wealthy matriarch of fictitious Genoa City, Wis.

Jeane's son, actor Cobin Bernsen, sent out this message via Facebook:

"My mother passed away this morning just a short time ago, peaceful with my sister by her side, in her sleep. I was going to visit this afternoon, thought I had time. Reminder to self - time is a precious thing. I too am at peace however. I said my goodbyes several times over during the last few weeks.

"I'll go one last time now for a gentle kiss a final farewell for this lifetime," he continued. "She has been a blaze her entire life, that beacon, that boxer I spoke of earlier. She went the full twelve rounds and by unanimous decision... won! And while her light finally gave into the wind that gives flight to all our journeys, there will always be a glimmer left behind by what she stood for. I will speak about that more in coming days, months I suppose. I will certainly dedicate what remains of my life to continue her purpose of honesty, equality, humility, empathy and love."

Jeanne Cooper, the 84-year-old soap legend of "The Young and the Restless" had been hospitalized mid April with an unknown illness in Los Angeles.

But she started making a comeback by late April. In a Facebook post on April 17, Bernsen said his mother cursed several times, "showing me that she's becoming her old self, not thrilled about the situation, and ready to get out of the hospital and shake up the world."

But in the end Cooper lost the battle and went peacefully to the other side.

The Emmy-winning star had won two Daytime Emmys and achieved ten Daytime Emmy nominations: nine for Lead Actress and one for Supporting Actress. She also had two Primetime Emmy nominations.

She also made guest appearances on "L.A. Law," playing the mother of Mr. Bernsen's character, Arnie Becker.

I personally know her best for her eerie performance on "The Twilight Zone" playing a barmaid in the Episode "Mr. Denton on Doomsday" and being hilarious on "The Nanny," playing herself in 1997.

President Steve Mosko of Sony Pictures TV, which produces the soap for CBS, also released this statement:

 "Jeanne Cooper was a legend in daytime and a beloved member of our Y&R family. She touched the lives of millions, who watched her every day over the past 40 years. We send our sincerest condolences to her family as we also celebrate her wonderful life."

Cooper married TV producer Harry Bernsen in 1954 and divorced in 1977. The couple had three children, all actors, Corbin, Collin and Caren.

Cooper had to take a medical leave from Y&R in 2011 when she had a horrible bout with the flu. Katherine was played briefly by Michael Learned, star of "The Waltons."

"You can have a life with this show," Cooper said recently about her longtime gig on Young and the Restless. "Lots of actresses say they want to do movie but that's for only three months. It all depends on where you want to hang your lights. If you want to be a movie star, then this is entirely different. I never wanted to be a movie star. I always wanted to be an actress, one of the best. And I am."

Cooper was a pioneer and an inspiration to all of her fans.

We are saddened to learn of the great actress's death and send out much love to her family at this time.