Metro

Stars go Gaga for the lady

What do superstars talk about? The same things we all do — dating, astrological signs, gender confusion . . .

It was Thursday night at Carnegie Hall, during Sting and Trudie Styler’s star-studded Rainforest Benefit Concert, when the grand dame of pop stars, Elton John, approached the current flavor, Lady Gaga.

“Did you break up with Matt [Williams?]” Sir Elton asks Gaga, referring to her stylist and on-again, off-again flame.

“No, why?” says Gaga, dropping the faux-English accent she occasionally employs.

“Oh, I read it somewhere.”

“Do you believe everything you read?” Gaga says. “I don’t have a penis either, Elton.”

Elton smiles, “I love Matt,” he assures her. “I just want you to be on your own!”

She shrugs him off and shimmies her shoulders to the music.

Backstage at the charity concert — which raised $3 million this year to fund literacy training and forest-management programs across Africa, Asia and South America — is a reunion of the Old Boys Club of rock ‘n’ roll: Sting, Elton and Bruce Springsteen are all in the house.

But tonight, the aging rockers seemed titillated by Gaga’s out-of-the-box persona.

What’s it like to be the world’s reigning pop queen? After jetting in from Germany on a 24-hour break from her European tour, she arrives dressed in a jet-black Calvin Klein corset contraption. Teenagers who catch an unexpected glimpse of her on 67th Street sob uncontrollably.

“Here’s what’s going on,” she instructs the orchestra. “I’ll sing ‘Stand By Me’ with Sting, then I will say something funny, hopefully, then I’ll go into ‘Speechless,’ and Elton will come on stage. I’ll say, ‘What are you doing on stage?’ and then we’ll start.”

While the other stars are each confined to a single dressing room, Gaga’s wardrobe alone requires two rooms.

One of her stylists arranges more than a dozen pairs of shoes, 24 sets of eyeglasses, two racks of clothing and dozens of head pieces. All for only three songs. “She never knows what she wants to wear until the last second,” the stylist says. “This isn’t even all of our stuff — some of it got held in customs.”

In the room next to Gaga, Springsteen is more low-key, sitting alone, poring over pages of handwritten notes and learning the lyrics to Journey’s “Don’t Stop Believin’, ” the grand finale.

The Upper West Side-bred Gaga finally emerges in a pair of gravity-defying platforms — little black booties with a thick wedge under the ball of her foot that allows her tiny heels to dangle in the air. “I would tell her to break a leg, but I can’t, not in those shoes!” whispers a stagehand.

Chris Noth, Goldie Hawn and Kate Hudson, hanging out in the wings, walk over to fawn.

“I’m Kate!” says the actress, dressed demurely in a pantsuit.

“Nice to meet you,” says Gaga, as the two inspect each other like paintings. They high-five when they realize they share the same astrological sign — Aries.

“You two are beautiful,” Gaga says to the mother-daughter team of Hawn and Hudson. “Is that fun to go out and be so gorgeous together?”

Gaga recounts to Noth the hard days before superstardom. “I used to be a total venue whore,” she says. “I would perform anywhere. I would call the Bitter End and tell them that I had discovered this amazing new artist, Lady Gaga, and how they had to book her immediately.”

About 10 minutes before Springsteen’s finale, the Boss descends, almost unnoticed, and a stagehand tapes up his shirt sleeves around his thick biceps. “He’s so good it’s not legal,” Gaga says.

Then she settles into a contemplative conversation with her producer, inspired perhaps by the rock legends around her. “It all has to mean something,” Gaga says, curling up in a folding chair like a little girl.

She wants to record more ballads — “I feel really comfortable doing stuff like that” — and explore “new vocal territory.” She admits she’s exhausted and that she slept for four days straight on a recent break.

But for now, she returns for a finale, sharing a stage with Debbie Harry, Dame Shirley Bassey, Sting, Springsteen and Elton.

akarni@nypost.com