Natalie Cole performs on stage at SeriousFun Children's Network's New York City Gala at Avery Fisher Hall, Lincoln Center, on March 2, 2015, in New York City. Credit: Dimitrios Kambouris/Getty Images

Natalie Cole's family revealed the Grammy-winning singer's cause of death on Thursday, January 7, saying she passed away from heart failure induced by lung disease.

Cole died on Thursday, December 31, at age 65. The “Miss You Like Crazy" singer, the daughter of the legendary Nat "King" Cole, underwent a kidney transplant in 2009, after battling drug issues and ensuing hepatitis. 

In a statement to the Associated Press on Thursday, her family said: "[Cole] responded well to pulmonary arterial hypertension-specific agents over many years, during which she performed many concerts world-wide, but eventually succumbed to intractable right heart failure, an outcome that unfortunately commonly occurs in this progressive disorder."

Cole detailed her struggle with substance abuse — include cocaine, heroin and alcohol — in her 2000 memoir Angel on My Shoulder. In 1983, the singer checked into rehab. Decades later, in 2008, she noted that her hepatitis C was brought about by her drug use.

Her family confirmed Cole's death in a statement to Us Weekly last week, saying: "Natalie fought a fierce, courageous battle, dying how she lived … with dignity, strength and honor."

Many celebrities grieved for the "Unforgettable" singer and took to social media to remember her. "Sending prayers and condolences to all the loved ones of my friend #NatalieCole! She will be truly missed but her light will shine forever!" Patti LaBelle tweeted on January 1.

Another music legend, Tony Bennett, added on Instagram: "I am deeply saddened to hear of the passing of Natalie Cole, as I have cherished the long friendship I had with her, her father Nat, and the family over the years. Natalie was an exceptional jazz singer and it was an honor to have recorded and performed with her on several occasions. She was a lovely and generous person who will be greatly missed."

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