Natalie Cole has died of congestive heart failure, ET can confirm.
The legendary singer died Thursday night in a Los Angeles hospital after suffering ongoing health issues. She was 65 years old.
"It is with heavy hearts that we bring to you all the news of our Mother and sister's passing," her family said in a statement to ET. "Natalie fought a fierce, courageous battle, dying how she lived..with dignity, strength and honor. Our beloved Mother and sister will be greatly missed and remain UNFORGETTABLE in our hearts forever."
WATCH: Natalie Cole on Singing Duets With Late Father
Reverend Jesse Jackson also tweeted about the news on Friday, writing, "Natalie Cole, sister beloved & of substance and sound. May her soul rest in peace. #Inseperable."
Last month, the "Unforgettable" singer canceled her New Year's Eve show at the Walt Disney Concert Hall due to health reasons. She also withdrew from a show scheduled for Dec. 2 in San Francisco, “due to a medical procedure which precipitated a lengthy hospital stay," the San Francisco Symphony announced in October.
Cole, the daughter of legendary singer Nat King Cole and former Duke Ellington Orchestra singer Maria Hawkins Ellington, had won multiple GRAMMYs, most recently for Best Traditional Pop Vocal Album in 2009 for her album Still Unforgettable.
Aside from her incredible singing career, she was also a talented actress, making guest appearances on such shows as Touched by an Angel, Law & Order: Special Victims Unit, and Grey's Anatomy.
Cole had also been open with her battle with drug abuse and recovery. Her 2000 autobiography, Angel on My Shoulder, was turned into a made-for-TV movie, Livin' for Love: The Natalie Cole Story, which aired on NBC that same year.
Cole was married three times, and has one son -- 38-year-old Robert Yancy -- with her first husband, songwriter and producer Marvin Yancy.
ET caught up with Cole in June 2013, when she talked about recording an album in Spanish, Natalie Cole en Espanol, which also included a duet with her father on "Acércate más" ("Come Closer").
WATCH: Natalie Cole Talks Epic Concert and New Album
"I think it's always a little bit bittersweet when I do it," Cole said of recording duets with her late father, who passed at age 45 from lung cancer, "but I do love to do it because I feel so connected to him. ... It's still emotional, but it still feels good, so you always still want to hold on to that feeling."