GaGa and Tony, who is battling memory-robbing Alzheimer's disease, teamed up for two farewell concerts at New York's Radio City Music Hall in August to celebrate the icon's 95th birthday, just before his family announced he was retiring due to the devastating effects of his condition.
"I witnessed something in that man that let me know that he knew [me]," the pop star told USA Today on Monday, October 4. "He called me 'sweetheart' during rehearsals, but on our last night together, he said, 'It's Lady GaGa.' That was the first time he had said my name in a long time. And he gave that gift to me. I know he dug deep to give me that gift and I'm really forever grateful."
The entire last show was very emotional for the "Bad Romance" hitmaker.
"My favorite moment was right after I was done singing when Tony went on stage and the curtain lifted up to reveal him," she recalled. "I planned that reveal for hours and hours and hours. And when he opened his mouth to sing 'The Best Is Yet to Come' with that spotlight on him, I just burst into tears with joy."
"For me, that was an absolute privilege to be a part of. I just wanted everything to be perfect for him during his last moments on stage."
The celebrated singer only spoke a few words during his final performance, but never missed a beat while singing.
"It was absolute magic," GaGa said. "I was so moved. I had to work a lot on breathing because I wanted to cry almost all the time, watching him just snap right into the moment."
"We also recorded some songs together while his Alzheimer's was beginning to change his nature, and it was remarkable that he [remembered every lyric]. It's a testament to music being in Tony's blood... My time with Tony has changed me forever. Frank Sinatra said he was the best singer in the world and I don't think Frank lied."
GaGa revealed she hasn't spoken to Tony since that last show, but talks to his family frequently. "I love him so much," she shared. "I miss him all the time, I pray for him all the time. I pray for his wife, Susan Benedetto, his sons, his family. I care very deeply for him."