Before Madonna and Gaga, before Bey and Björk, there was Cher. She’s always been a singular sensation, thanks to her deadpan humor, uncommon contralto and fierce, take-no-prisoners fashions. Even now, on the heels of her 26th album, “Closer to the Truth,” the beat goes on as her “Dressed to Kill” tour rolls into Barclays Center Friday. Here, Cher shares with The Post — about her ex husband and Svengali, Sonny Bono; Cyndi Lauper, longtime friend and opening act; and what she can’t resist in NYC. And yes, those outfits: Cher turns 68 soon, but don’t expect her to cover up.
Your “Living Proof: The Farewell Tour” wound up in 2005. Wasn’t that supposed to be goodbye?
I thought so, too! If the [new] album hadn’t been a hit, I would have never toured again. And then I realized, I would never be able to do it again. That was kind of shocking . . . that there won’t be another tour, that you won’t be able to do it, even if you want to.
Will you and Cyndi sing duets?
No. Cyndi has a set she does, and I come on after her. There’s no one I’d rather have open for me. She’s a hard act to follow. She never stops moving, her voice is as great as it ever was . . . Sometimes I think, “Oy, this might have been a dumb thing. Maybe I should rethink this!”
What’s your favorite song of hers?
“True Colors.” It just kills me every time.
Audiences seem touched by your duet with an onscreen Sonny. Is this the first show in which you’ve embraced him like that?
We had “Sonny and Cher” footage on the last tour, but I never wanted to do “I Got You Babe.” It was just something I never could do. And then I thought, “Well, you better just do it. Pull up your big-girl G-string and do it.”
There was always talk that Sonny controlled you . . .
That was true. Look, he was 29 and I was 18 [when we got married]. And he knew about the record business and I didn’t. And it was just Son’s personality to be the boss.
He was a congressman when he died. Think he’d have gone further?
He seemed well-loved in Washington, so I’m sure he would have. But he was a different kind of Republican, [at a time] when Republicans and Democrats played cards and talked until the wee hours. I don’t think he would have liked politics today.
Where do you stand?
I guess I’m very progressive in some things, and maybe more conservative in a few things, but I’m certainly not a Republican. I’m not a Democrat, either. I’m disappointed in politics, because I think the one thing it doesn’t do is serve the people. I’m still a child of the ’60s.
You’ve taken a lot of career risks. What was the biggest?
Leaving Sonny. I’d been with him since I was 16. Son was very hot-house plant with me. I didn’t really have any freedom. I walked away from the show, from everything, but I just didn’t want to stay anymore. Eleven years was enough. I wasn’t my own woman then, but I wanted to be.
Rumor has it you were nearly cast in “Cats.”
I could have been, but no one asked me.
You’ve tweeted about writing a Broadway show of your own.
Actually, I’m helping with it, because no one knows what went on in my life but me. It’s a story with three Chers in it — young, medium Cher and the old Cher. They sing together, they sing apart.
Would you perform in it?
Actually, I could play the old Cher quite well.
You don’t look it. Exercise? Diet?
I was a tomboy my whole life. When I met Sonny, I was playing softball still. I’ve always exercised — when we did the show, I worked out with the dancers. Only in New York do I have two downfalls: John’s Pizzeria and Serendipity’s frozen hot chocolate. I’ve been going to Serendipity since I was 19 years old. I’ve had my kids’ birthday parties there. I’ve had a frozen hot chocolate every single day I’m in New York.
When have you lived in New York?
I’ve lived there three different times. I loved it from the first time I went there. I was 14, and I remember walking outside my building and thinking, “Oh my god, I’m free! I can go anywhere!” When I was making “Moonstruck,” I was living across the street from the Met [Opera House], and then I bought this other apartment I really loved, at the Silk Building. Every time it’s fall and I go to New York, I want to buy an apartment.
Tell us about that headdress you’re wearing on this tour. It looks so heavy.
It’s not heavy, it’s just very unwieldy. Like, when we’re going to the stage, people will yell, “Sideways! Sideways!” because it’s so wide sometimes you can’t keep walking straight.
So many shows, so many outfits. Out of everything you’ve worn, what’s caused the biggest flack?
Oh, maybe the costume I wore for “[If I Could] Turn Back Time.” It got banned from MTV. [Notably, Cher revived the 1989 look for the 2010 VMAs.]
So who’s carrying the torch for outrageous dressing now: Katy Perry? Miley? Gaga?
The important thing is that everyone does their own thing — that’s the torch! You pave the way for everyone to do whatever it is they want. I got in trouble for everything I wore, and now you can pretty much wear anything.
How best to describe your voice?
It’s not a man’s voice, it’s not a woman’s voice, it’s somewhere in the middle. I’m not particularly a big fan of it. I wouldn’t listen to my records, but people seem to like them.
If you actually could turn back time, what would you change?
I never think in terms like that. Your life makes you who you are, so your mistakes are as important as your successes. Failure is highly underrated.