There is no amount of names you can drop, palms you can grease or cleavage you can show that will get you into the strangest VIP room in New York City. The only key you need for this secret spot in Forest Hills Stadium is a 9-volt battery — and the ability to act like you need to go … to the bathroom.

The former home to the US Open, which also hosted shows in the ’60s and ’70s by The Beatles, Hendrix and Dylan (who is playing Friday night with Mavis Staples), was revived as a concert venue in 2013. Further refurbishments have been added year by year to the Queens venue ever since, and include the party-potty and a few other well-hidden hangouts dotted around the venue.

If you’re a VIP or a friend of concert staff, you’ll head for the blue plastic john and use that battery to open a makeshift lock. (They tell you the location of the room, give you a battery and show you how to open the door.)

Once you do, you’ll enter a rock ’n’ roll Narnia filled with sofas, a prime view of the show and a plentiful supply of free booze.

“We thought it’d be funny if people standing in line for the [real] porta-potties suddenly saw 20 people come out of one, like a clown car,” says Mike Luba, president of show promoter Madison House Presents.

Most concertgoers are none the wiser. In fact, the party-potty location is so well-disguised, even people in the know have trouble finding it. “Half the time, people trying to find the room open the door to a potty and just find somebody taking a leak,” a member of the stadium security crew said with a laugh at a recent Dolly Parton show.

‘We thought it’d be funny if people standing in line for the [real] porta-potties suddenly saw 20 people come out of one, like a clown car.’ - Show promoter Mike Luba

It’s just one of the secrets the stadium has slowly revealed during the past three years of renovation. As staffers cleared away debris amassed for decades, they’ve turned some nooks and crannies into rustic, oddball hangouts around the stadium floor.

One spot is known as the Raccoon Room — so-called because a family of raccoons was discovered inside it, one of them eating a Milk Dud. Today it holds a self-serve bar fashioned from a former toolshed. Those lucky enough to be admitted — a password that changes with every event gets you in — can watch the show from small viewing windows. Sitting atop the bar is a taxidermied raccoon holding a box of Milk Duds.

A short walk away is the Sign Room — also password-protected — where the US Open’s sign painter once worked. “We’re pretty sure he was living or at least sleeping in [it],” Luba says. “When we found this place, there was a cot in it.” Hand-painted signs and panels bear the names of professional and amateur tennis players, while concert posters promote post-refurbished Forest Hills shows by the Replacements, Ed Sheeran, The Who and Mumford & Sons. “Without naming names,” Luba says, “it’s not unknown for artists to utilize these spaces to party well after the crowd has gone home.”

Some things in rock ’n’ roll never change.