Due to Alzheimer's, Tony Bennett's memory was fading. Then he remembered Lady Gaga's name onstage.

Tony Bennett, the smooth American singer who had an enduring hit with 'I Left My Heart in San Francisco', has died at 96.

He died at his home in New York City on Friday of age-related causes, his publicist Sylvia Weiner said in a statement. Bennett had also been dealing with the effects of Alzheimer's disease, which he was diagnosed with in 2016.

The famed jazz singer was called "the best singer in the business" by no less than Frank Sinatra, and Bennett won 20 Grammy awards, including a lifetime achievement award.

Hollywood and the music industry's elite are now paying tribute to Bennett, including the likes of Elton John, Bill and Hillary Clinton, and Martin Scorsese. It was Bennett's enduring friendship with Lady Gaga though that perhaps younger fans remember best.

The pair were very close friends for a number of years, and everyone remembers the moment in 2021 when Bennett and Gaga did their last performance together. It was particularly touching considering Bennett recognised Lady Gaga and said her name - given the memory loss he faced in his final years due to the Alzheimer's.

What the moment Tony Bennett recognises Lady Gaga on stage. Post continues below.

Bennett was in his late 80s when he recorded a 2014 album of duets with Lady Gaga and went on a world tour with her in 2015. The pair continued to perform together over the years and write music.

"We were fast friends – friends ever since our first meeting," Lady Gaga told PEOPLE in 2014. "Tony heard me sing, and he asked to meet me after the show. And I said, 'Oh my gosh! Tony Bennett's here!'"

For Bennett, he recounted to ABC News: "Ever since then, we've just been close. We just love performing with one another. She's terrific. "She is so spontaneous and improvised. What's interesting about her, other than any person I ever met in the entertainment world, she changes from day to day."

In 2014, Lady Gaga asked Bennett to draw her a trumpet, and he sketched her a Miles Davis' trumpet. She then had it tattooed on her with Bennett's last name, Benedetto, so that she "would always remember this time together".

It was in 2021 that they had their final concert together where Bennett recognised Lady Gaga on stage. She told a 60 Minutes special that moment was extremely special to her. 

"That's the first time that Tony said my name in a long time. I had to keep it together because we had a sold-out show and I have a job to do. But I'll tell you when I walked out on that stage and he said, 'It's Lady Gaga,' my friend saw me. It was very special."

Reflecting on her last performance with Bennett, Lady Gaga said: "It's not a sad story".

"It's emotional. It's hard to watch somebody change. I think what's been beautiful about this, and what's been challenging, is to see how it affects him in some ways, but to see how it doesn't affect his talent," she explained.

"I think he really pushed through something to give the world the gift of knowing that things can change and you can still be magnificent."

As Lady Gaga wrote on Instagram recently: "Believe in love and partnership, even with 60 years between us, and Alzheimer's, there is nothing like the magic of music. I love you Tony, and the world loves you too. How could they not?"

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Discovered by Bob Hope who saw him singing in New York's Greenwich Village and made him an opening act on his TV show, Bennet became one of the most popular singers of the 1950s before the rise of rock'n'roll undermined him.

As the rock era began, Bennett moved away from pop songs toward jazz. In the next phase of his career, Bennett recorded 'I Left My Heart in San Francisco' in 1962, which reached only No. 19 on the Billboard chart but became his signature song.

"People ask me, 'Don't you get tired of singing that song about San Francisco?'" Bennett said in a Reuters interview. "I say, 'Do you get tired of making love?'"

Bennett was also known for his social justice work - from marching side-by-side with Dr Martin Luther King and refusing to perform in apartheid-torn South Africa.

In his autobiography, Bennett wrote: "When the march started, I had a strange sense of déjà vu. I kept flashing back to a time twenty years earlier when my buddies and I had fought our way into Germany [in World War II]. I'm enormously proud that I was able to take part in such a historic event. But I'm saddened to think that it was ever necessary and that any person should suffer simply because of the colour of his skin."

Over the years, his star continued to rise and he continued recording best-selling music. Partners on his popular duet albums ranged from former Beatle Paul McCartney and soul queen Aretha Franklin to country star Willie Nelson and U2's Bono.

He marked his 90th birthday in 2016 with a party in New York that drew celebrities such as Bruce Willis and John Travolta. The Empire State Building even put on a light show in his honour. 

It was in early 2021 that Bennett shared he had been diagnosed with Alzheimer's Disease in 2016, but he kept recording after the diagnosis and later tweeted, "Life is a gift - even with Alzheimer's."

Due to his illness, Bennett retired from performing after his final concert at Radio City Music Hall On August 3 and 5, 2021.

Bennett's wife Susan Benedetto explained in a profile published in AARP The Magazine that the progressive memory loss associated with Alzheimer's was getting worse. Over the years, she said he struggled to recognise a lot of people, only still recognising a select few loved ones. But his music was something that never wavered.

"Singing is everything to him. Everything. It has saved his life many times," she said.

Benedetto later explained on 60 Minutes: "I mean that's the other thing about music that sets it apart, is that it is a part of the brain that's very emotional. Music is housed in different parts of the brain, including parts of the brain that deal with emotion, and therefore, it's easy to be moved by it when you hear it."

Following the news of Bennett's death, Nancy Sinatra said he was "one of the most splendid people that ever lived", and Barack Obama also gave a touching tribute.

Tony Bennett was an iconic songwriter and entertainer who charmed generations of fans. He was also a good man—Michelle and I will always be honored that he performed at my inauguration. We're thinking of his wife Susan, his kids, and everyone who is missing him today. pic.twitter.com/TglWTA06Zm

— Barack Obama (@BarackObama) July 21, 2023

Elton John said: "He was the classiest singer, man, and performer you will ever see. He's irreplaceable."

Billy Joel also shared a tribute, saying Bennett was "one of the nicest human beings I've ever known".

"Tony Bennett was one of the most important interpreters of American popular song during the mid to late 20th century. He championed songwriters who might otherwise have remained unknown to many millions of music fans," Joel wrote. "He was a joy to work with. His energy and enthusiasm for the material he was performing was infectious."

For Bennett, he always said that regardless of age or his health, he would continue singing no matter what.

"I have no desire to retire," he said to ET. "I paint every day and I sing every day. I want to prove I'm not giving up on life, because life is beautiful. I hope to prove that if you don't give up on it, you can actually improve and get better as you get older. I've never worked a day in my life doing the thing that I love - singing."

Feature Image: Getty.

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