The 85-year-old singing legend worked with GaGa for his recent Duets II album project, where they duetted on 'The Lady is a Tramp'.
He revealed that he considers the 'Born This Way' star as one of the most interesting artists he has ever worked with.
"She is becoming the Picasso of music. She's very talented," he told BBC Breakfast.
"She's different than every performer that I've ever met in my whole career. She recreates herself on a daily basis. I can't believe her energy and intelligence."
Bennett also praised the late Amy Winehouse, with whom he collaborated for a cover of 'Body and Soul'.
"She was a great jazz singer. It was regretful that she died so young.
"She really was one of the greatest jazz singers of all time."
Speaking about his own history with drug and alcohol addictions during his early career, he said: "I was smart enough to stop at a young age. It happens to all performers.
"In the early 1960s, you get helium in the brain once you become successful. You make a lot of wrong moves at first.
"I asked [Woody Allen's manager] about someone on drugs. He said that 'he's sinned against his talent'. When I heard that sentence, I immediately dropped everything, alcohol, cocaine, marijuana."
Bennett - who is currently touring the UK - said of his long career: "I could have stopped 15 years ago. I have a very strong passion, my ambition is to get better as I get older, and it's working."
Lady GaGa and Tony Bennett have recently been rumoured to be working on a full album together.
Watch their 'The Lady is a Tramp' duet below: