Madonna kisses boxer beau Josh Popper at US ‘Celebration’ tour kickoff in Brooklyn

Strike a perch — there’s nothing to it.

While it’s been great to watch how much of Madonna’s “Celebration” Tour has lived up to its name — in honor of her 40th anniversary in music — one of the most fun parts has been seeing which surprise guest will take the judge’s seat alongside the Queen of Pop during “Vogue.”

Since the tour opened in October at the O2 Arena in London, so far everyone from her oldest children, Lourdes Leon and Rocco Ritchie, to designers Donatella Versace and Jean Paul Gaultier to FKA Twigs and M’s longtime friend Debi Mazar has taken that seat of honor during the ballroom scene. 

And to kick off the US leg of her tour at Brooklyn’s Barclays Center on Wednesday night, Madonna could’ve certainly had her pick of celebs to bring it back to where it all began, in New York.

The diva returns to the BK arena on Thursday and Saturday before Madison Square Garden dates on Jan. 22, 23 and 29.

But instead of going starry, she went sentimental, calling up her boyfriend, boxing coach Josh Popper. He trained Madonna’s 18-year-old son, David Banda, at his Manhattan gym Breadwinners, and the two have been romantically linked since early this year.

And their May-December romance — he’s 30, she’s 65 — was on sweet display at Barclays Wednesday. Although Popper was a little more reserved than some other judges, as he basically received lap dances from both women and men with his girlfriend right beside, his big smile said it all as he embraced her big night — and her world.

And perhaps not so coincidentally, the hot highlight of the show, Madonna’s 1992 hit “Erotica,” is set in boxing rings, with dancers blurring the lines between pain and pleasure and mistress Dita — the singer’s dominatrix alter ego from that era — clearly being the one in charge.

There are more guests close to Madonna’s heart in the show. In addition to her 11-year-old daughter Estere fiercely working the runway during “Vogue,” there’s Banda on guitar, in “Mother and Father” and “La Isla Bonita”; daughter Mercy James, 17, on piano for “Bad Girl”; and Estere’s twin, Stella, hoofing it up to “Don’t Tell Me.”

“I’m the luckiest mother in the world,” said Madonna.

“I get to perform every show with four of my six incredible, amazing children.”