The 88-year-old crooner - who teamed up with Gaga, 28, for their new jazz album 'Cheek to Cheek' - believes the collaboration has brought out the best in the 'Pokerface' hitmaker and insists she has ''never been happier in her life''.
The 'Anything Goes' singer added that, with his help, Gaga has managed to ''shock'' fans with her latest offering following the mediocre success of her most recent solo album 'Artpop'.
He told [email protected], at the Exploring the Arts gala at Cipriani 42nd Street in New York last night (30.09.14): ''(Cheek to Cheek) speaks for itself, see. People are shocked by how wonderful she sings the great American standards.
''I steered her toward quality and she picked up on it right away. She's never been happier in her life.''
Tony recently admitted he is keen to work with the Grammy Award-winner ''as many times as possible in the future''.
He said: ''There were no moments of craziness or eccentricity when I was with her. She said that when she was 13 and singing jazz, 'Nobody ever paid any attention to me.' We get along great and she's just such a good improvised jazz singer. I think the public are going to say, 'I knew she could sing well but I didn't know she could sing THAT well'.
''I just love her and want to work with her as many times as possible in the future.''
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