In the stylishly shot “Tony Bennett: Duets II” making its bow tonight on PBS’ “Great Performance,” everybody dresses up for the recording studio.

Bennett naturally is always wearing a snappy suit, but many of those joining him, including Faith Hill, Norah Jones and Carrie Underwood, are wearing fancy gowns.

For Bennett, the elegance is a matter of course. “I like being dressed up,” he told reporters at the TV Critics press tour earlier this month, following a mesmerizing dinner concert with his trio. “It’s called being civilized.”

For the others, maybe it was paying respect to the great standards they sang together.

But recording the “Duets II” album, the only No. 1 album from someone as old as he – 85 — was historic in another aspect as well: It was the last recording session for Amy Winehouse, who died in July.

Bennett recalled how it came about:

“I was playing Royal Albert Hall for two nights in Great Britain, and she came back with her dad and her boyfriend. And she said, ‘You know, two years ago I won a Grammy, and I wasn’t excited about winning the Grammy but that Tony Bennett announced it,’” he said. “She was a big fan of mine, and I was very surprised because she’s so young.”

But when he thought of those who joined them who really sang “traditionally correct,” “It ended up being Amy,” says Bennett, who joined her on a version of “Body & Soul.” “She just had the gift of knowing how to sing as good, and was influenced by, Billie Holiday, Dinah Washington, Ella Fitzgerald.”

“Her dream was to become very, very famous doing that,” Bennett said wistfully. “But my son called up two months after we did the record and tragically told me that she died, and the whole world went, ‘Woof.’ They couldn’t believe it, especially in Britain.”

Several months later she met with Winehouse’s parents when they were visiting in the U.S. “She said, ‘You know, everybody feels so tragic about her dying, but as a mother,’ she said, ‘I’m very different.’ She said, ‘All I know is her whole life she wanted to she acquired she actually did what she really wanted to do, and she became world famous. And to me, even though she had a very short life, she had a very successful life because what she really wanted, what she dreamt about her whole life happened,’ and that was so different than anything I ever heard a mother say about this tragedy that the whole world felt so bad about.”

Bennett, who also sings with Willie Nelson, Andrea Bocelli, Michael Buble and Alejandro Sanz on “Duets II,” sounded like he was most struck by the young women he sang with.

“You know, you meet performers, and then all of a sudden you meet someone that has a touch of genius,” he said, referring to Lady Gaga. “She’s highly intelligent, highly creative. She knows so much about performing. She sings magnificent.

“This album surprised me because all of the artists in the album all came out of art schools,” he says, mentioning Berklee and Juilliard.

“And Lady Gaga is from NYU. So they all had teachers that really told them what to expect and what to do and how to do it right. So by the time they came to us, they were all so professional,” Bennett says. “Like Lady Gaga, when she finished recording, she went around to the whole crew and told every thanked everybody for believing in her and being so good to her. It was a wonderful you know, you only see that years ago I would see that with the great professionals like Jack Benny or George Burns or Frank Sinatra, where they would really appreciate everybody that helped them out. And here’s this young group of artists that already eliminated seven years of learning how to perform. They were ready to perform.”

I asked Bennett if the young duet partners weren’t also intimidated by sharing the microphone with a singing legend of seven decade standing.

“No, they weren’t like that,” he said. “They were all they learned from their teachers and good schools what to expect, and they were all very professional.”

But when it comes to performing, “I’m nervous too.”

Which, he said, is important. “You have to have butterflies. Everybody thinks that if a performer is nervous, that it’s a negative thing. That’s not true. It’s just that they have the butterflies going, hoping that the lights work and hoping that the sound works and hoping that the audience is going to enjoy it.

“I’ve just seen it with the greatest masters, like Duke Ellington and Frank Sinatra and Lena Horne. Before the show, they were just saying, ‘Wow, I hope it all works.’ Then after the show they know it’s that it’s that adrenaline that makes a thing happen. I mean, if you don’t care about whether the audience is going to like it, why should the audience like you? So if you show energy, you know, and care about what you’re going to do, the audience is going to respond that quick right back at you. And the ones that fail are the ones that don’t care whether you like it or not.”

Hence, he says, schooling in music and art is important from the very youngest ages.

“I want every public school in the United States to have art programs,” he declared. “Whenever there’s a war, they say, ‘We have to cut the arts.’ And, you know, Winston Churchill, when they told him, ‘We have to cut the arts’ in the Second World War, he said, ‘What else are we fighting for?’

“This country is so beautiful that we should actually have we should teach the world about truth and beauty, which is what the arts are all about. That’s what it’s about. It teaches us to become civilized.

“And the more we could do that, that’s what we should do because we’re every nationality and every religion. And it’s the only country in the world that has that. And we should never forget that. We should really help the rest of the world show us the way and remind everybody in the world that we’re all here on this little planet in the universe, and everybody’s here, and everybody’s important, and they shouldn’t be treated like someone’s better than someone else. That’s nothing but pure greed and ignorance. Everybody on the planet is here, and we should all we should just try and educate as many people as possible.”

And what people would learn would be those great American standards, which contrast so much with what he calls “the day and age of obsolescence that we live in today.”

“There was a renaissance period in a very young country called the United States in the ’20s, ’30s, and ’40s that they call it the Great American songbook,” Bennett says. “I call it the Fred Astaire Songbook because George Gershwin and Irving Berlin and Cole Porter would never have a song introduced unless Fred Astaire introduced it.

“And those songs are never going to die. Frank Sinatra is never going to die. Nat King Cole is never going to die. Ella Fitzgerald is never going to die. They’re not old. They’re forever. And no country in the world has ever given that many beautiful, popular songs through Broadway and movies when soundies first came in. No country in the world has ever given the rest of the world so many glorious folk songs. And I’m absolutely convinced that within 35 years, it won’t be called light entertainment. It’s going to be called America’s classical music: Cole Porter, Gershwin, Harold Arlen, Johnny Mercer, Jerome Kern — you can’t get better. And now we have Stephen Sondheim. And it’s just great, great music, and it’s never going to die.”

Part of the secret of his own longevity, he says, is simply “I don’t sing a bad song.” Also, he never was reduced to trends. (“I wasn’t doing disco or whatever”).

“I don’t have the gift of writing songs like Cole Porter, who wrote better than anybody, or, musically, Jerome Kern, who was the top of the Christmas tree when it comes to music. So I just go for top quality,” Bennett says. “I think the public deserves that. I dislike any performer that looks down at the audience like they’re idiots and they think they’re superior to the audience. I think they’re failures. Any performer, I don’t care how much applause they get or how much money they’re making, if they look down at an audience, they’re fools because the audience en masse — I always feel I’m singing as to an audience, and I consider them as a whole result — I’m singing to a genius, because they’re quick.

“I remember when I was a child singing vaudeville at the Paramount Theatre, and when someone came out on the stage, I could tell by the way they were walking to the center of the stage and I was just a child, but I could say, ‘This guy’s going to be good,’ just by the way he walked, the energy he had or the attitude he had.

“If you walk out sluggish and tired, the audience is going to be tired. If you really show up and you’re right on, the audience is right on for you. They’re with you. They’re not against you. The audience is not an enemy. They’re your friends. They save up hours and hours and years and years of money that they could really use for their own homes, especially in hard times, and they’ll save money up just to come and save enough money to come and get a ticket for an artist that they like. And they should not be disrespected.

“I grew up in an era, because of the Depression that we lived in, if an artist wasn’t any good, he just got booed. And in Harlem they used to have they used to have a pigskin, and if someone was bad, they’d boom! They’d hit him on the head to get him off the stage. They just wanted something very good. And they were right. The public is the best critic in the world. The public. And they’re intelligent, and they shouldn’t be treated like morons.”

“Tony Bennett: Duets II” plays on “Great Performances” tonight on PBS at 9 p.m. (Check local listings).