Publicist Sylvia Weiner confirmed Bennett’s death to The Associated Press, saying he died in his hometown of New York just two weeks shy of his 97th birthday.
One of the last of America's great crooners, Bennett released his first album in 1952 when he was in his mid-20s and went on to chart in the US in every subsequent decade of his life.
Bennett picked up his first Grammy for his signature 1962 song, I Left My Heart In San Francisco.
He was diagnosed with Alzheimer's disease in 2016 and went public five years later.
With more than 70 albums to his name, Bennett is perhaps the only artist ever to have had new albums charting in the US in the 1950s, '60s, '70s, '80s, '90s, 2000s, 2010s and 2020s.
In 2014, he broke his own record as the oldest living artist to hit the top of the weekly Billboard 200 album chart.
Performing well into his 90s, even after being diagnosed with Alzheimer's disease in 2016, Bennett was an entertainer beloved by all generations; Gaga was just one of the modern-day artists he collaborated with in later years.
Paul McCartney, John Legend, Christina Aguilera and Michael Bublé, as well as Sinatra, all feature on the long list of stars he worked with.
His 2011 duet with Amy Winehouse, Body And Soul, was the last song she recorded before her death.
