How Mariah Carey turned Christmas into a second career

During the hour that Mariah Carey made the audience wait for the start of her Beacon Theatre Christmas concert on Wednesday night, a row of superfans could not be contained. 

As tunes ranging from Nat King Cole to Run-DMC came softly out of the speakers, her admirers grew restless for their sacred time with the Suffolk County siren. A curly-haired middle-aged woman in glasses finally couldn’t take it anymore. She threw her head back and yowled from the depths of her soul, “Mariiiiaaahhh!”

This moment of religious rapture turned positively convulsive when Carey, wearing a silver gown into which she had apparently been sewn, finally appeared onstage to sing “Hark! The Herald Angels Sing.” The superfans shot out of their seats — dancing, screaming and embracing each other in a paroxysm of adoration, joy and desire.

One dancer, Bryan Tanaka, 33, rumored to be Carey’s new flame following the dissolution of her engagement to billionaire James Packer in October, escorted the singer as she walked down a series of steps to sing “O Holy Night,” the kind of showstopper that proves she still has what most singers don’t — her justifiably famous whistle register, the highest the human voice can achieve.

Carey’s glittering string of Christmas concerts in NYC — now in its third year and running through Dec. 17 — recall her 1990s glory, but the 46-year-old voluptuary is also looking forward by busily extending her brand beyond the stage. In May, she struck a deal with the Hallmark Channel to produce and star in three upcoming movies, and her first television series, “Mariah’s World,” debuted on E! this past Sunday.

“We started out and I got very protective,” Carey, who calls “Mariah’s World” a “tour doc” rather than a reality series, told The Post earlier this week at the Empire State Building. But she says she relaxed as she became better acquainted with the production crew.