The duo met Prince Harry while at a charity concert in London in June 2015.
In 2015, the pair won the Grammy for best traditional pop vocal album for Cheek to Cheek.
It wouldn't be the last time that the pair were nominated for Grammys: in November 2021, the 36-year-old pop star and 95-year-old legendary singer were nominated for six Grammy Awards for work on their joint album, Love For Sale.
Gaga was on hand to celebrate her pal's 90th birthday in August 2016 in N.Y.C.
The pair reunited for a second album in 2018, a Cole Porter tribute album called Love for Sale. It was released in 2021.
"I think it was the next day, after the record released and had gone No. 1, he said, 'I wanna make this Cole Porter record with you,' and I said I would do it, and then guess what?" Gaga said in a trailer for Love for Sale. "We did it!"
"She's got so much talent that the minute we're together, something very good happens between the two of us," Bennett adds.
In August 2021, the pair reunited for a concert at N.Y.C.'s Radio City Music Hall. The concert, titled One Last Time, came several months after Bennett's family revealed that he lives with Alzheimer's disease.
In a memorable moment from the concert, Bennett remembered his old friend, Lady Gaga, as she came out onto the stage. Of the emotional moment, Gaga shared on 60 Minutes, "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.
Lady Gaga said after Grammy nominations were announced, "Tony is one of my most favorite people on the whole planet and I love him with all my heart. I love his family with all my heart, I love his wife, Susan, with all my heart. I can't tell you how much I learned from him and what it's like to sing with a legend for so many years."
Gaga received a nomination for her power ballad "Hold My Hand" featured on the Top Gun: Maverick soundtrack at the 95th Academy Awards ceremony. She was honored in the "Best Original Song" category.
Not only did the Academy recognize her for her work, but Bennett showed his love and support for her on Instagram. "Congratulations to the amazingly talented Lady Gaga on her 4th Oscar nomination!" he began.
"Today, #LadyGaga makes history as the first artist to receive three nominations in the 'Best Original Song' category at the #Oscars. So proud of you!" Bennett concluded.
