Tony Bennett has led the tributes to iconic singer Natalie Cole, who died on Thursday (31Dec15) aged 65.

The Unforgettable performer passed away in a Los Angeles hospital on New Year's Eve, and while the cause of death is yet to be confirmed, the star had scrapped a series of recent concerts, including a New Year's Eve gig at the Walt Disney Concert Hall in Los Angeles, due to complications from ongoing health issues.

"Natalie fought a fierce, courageous battle, dying how she lived... with dignity, strength and honour," a statement from her son Robert, and sisters Tomolin and Casey Cole read, reports the Associated Press. "Our beloved mother and sister will be greatly missed and remain unforgettable in our hearts forever."

Having spent more than 40 years in the music industry, having followed in the footsteps of her famous father Nat King Cole, news of her death provoked a flurry of tributes from her peers, with legendary jazz singer Tony Bennett posting a heartfelt message on Instagram on Friday (01Jan16).

"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," the 89-year-old began. "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."

Natalie's talents clearly left their mark on young and old alike, with American Idol winner Jordin Sparks, 26, also paying her respects on social media, as well as recalling the time she had the chance to sing Natalie's hit This Will Be (An Everlasting Love) with her a few years ago.

"I don't remember what I sounded like, I was too much in awe of her," she said in her lengthy Instagram tribute. "But, I sure remember her standing next to me, voice so pure & clear as a bell. I will never ever forget that moment. She was always so kind & exuded so much grace. Rest in everlasting love. I'm sure the heavens are absolutely loving you and your dad rejoicing together. 'Unforgettable in every way....' That you are, Natalie, that you are."

Rosie O'Donnell, Reverend Al Sharpton and Lenny Kravitz were just some of the other celebrities to pay their respects online.