“Having an 85-year-old guy sing better than he did when he was 80 really makes you think about how to preserve one’s life. He also comes from the Frank Sinatra school of doing things quickly, in the fewest amount of takes possible. But he’s a complete gentleman to the youth.

“Danny, his son, and Dae Bennett, his other son who was the engineer, co-produced the album. This let us surround Tony in comfort. The fact that they also made a documentary is amazing, because there were quite a few times when they had to stay out of the way when they needed the shot.

“The list of performers on the album came from Danny. We needed to represent the youth, but it was funny because Tony would look at the names and say, ‘Why do they want to sing with me?’

“The recording of Amy Winehouse was very difficult for the obvious... and we were worried about it. Amy really loved Tony – she had been to many of his shows. She was scared, but she was also a wonderfully attentive student. Tony and I talked with her about how we heard Dinah Washington in the way she interpreted the song. In the world that I live in, having Dinah Washington on your side is pretty special.

“There’s a point in the documentary where Amy gets so nervous and uncomfortable. She says, ‘That’s not good enough. I can do it better.’ She signals to stop the cameras, and asks for them to leave the room, which they do. That’s when the performance starts to come.

“Amy and Tony were so youthful together. There was such a history of sound coming from the two of them.”