The curtain opened, the lights shined and the show began.

No, this wasn’t Broadway and these weren’t actors, but the entertainment value was as Big Apple as it gets as Conor McGregor hosted the UFC 205 news conference inside The Theater at Madison Square Garden on Tuesday night.

Oh, sure, 11 other fighters and one UFC president were on stage as well. But from the very first question, McGregor took charge of this production.

The UFC featherweight champion began to respond to a question asking for a prediction for his Nov. 12 fight against lightweight champion Eddie Alvarez, who then suggested McGregor “be careful” with his answer.

“Or what? Or what? What you gonna do?” McGregor barked back. “Shut your mouth. I run New York . . . And ‘Mystic Mac’ predicts I’m gonna KO you inside one round.”

The crowd of approximately 2,000 roared as McGregor-laden crowds do, as New York crowds do. And this news conference to kick off Friday’s ticket sales for the historic card was something of a geographic celebration. A dozen fighters, including four champions and two former champions, were there to promote their fights in a place once thought to be a pipe dream for many.

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New York legalized MMA last March when the State Assembly voted to overturn the ban enacted in 1997 under Gov. George Pataki. That law took eight years of lobbying and politicking and educating to overturn. UFC officials always promised a massive card for the New York City debut. Three title fights, including the biggest star in the sport in McGregor, certainly qualifies.

“When we finally got New York done and we were coming to Madison Square Garden, I wanted to bring the best card possible here,” UFC president Dana White said. “This is the biggest card we’ve ever done.”

Tyron Woodley will defend his welterweight title against Stephen Thompson, and Joanna Jedrzejczyk will defend her strawweight title against Karolina Kowalkiewicz. White also said he added a matchup between top lightweights Khabib Nurmagomedov and Michael Johnson.

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Chris Weidman, the former middleweight champion from Baldwin who campaigned in Albany and elsewhere to get the sport legalized here, finally was added to the card Tuesday morning after some contract negotiations. He’ll fight Yoel Romero, a former Olympic silver medalist in wrestling for Cuba.

“This last week, Dana will tell you, has been crazy, we made it happen, I’m here,” Weidman said. “I’ve been envisioning this for so long.”

News conferences are for putting words to those visions. Few do it better than McGregor.

“I’m gonna be hitting him from everywhere,” McGregor said. “Sooner or later he’s gonna fall. One of those elbows, one of those shots is gonna dig into that soft sweet spot in the temple and that’s all she wrote. Two-weight world champion. UFC history. New York. The Irish are back!”