Mariah Carey at Hudson's Bay

TORONTO — Fireworks, an explosion of white confetti strewn into the night air and Mariah Carey singing “All I Want for Christmas Is You” before thousands of street-crammed fans set the stage for the first joint unveiling of holiday windows at Saks Fifth Avenue and Hudson’s Bay in Toronto on Nov. 3.

“These windows are a gift from us to the city…and to visitors alike,” said HBC chief executive officer Jerry Storch just moments before welcoming Carey, the singer with the famed, five-octave range, onto a stage built outside the joint entrance to the department stores’ Queen Street flagships.

Finally unwrapped, the Bay’s five animated “Enchanted Forest” window displays portrayed a veritable winter wonderland for 2016, filled with twinkly gaggles of geese sporting holiday wreaths and snow shoes, dancing raccoons, frolicking mice and bunnies skating on an icy forest pond.

Set in fantasy music boxes, Saks transported viewers to a “Land of 1,000 Delights” this year where hand-painted mannequins twirled atop their wind-up pedestals dressed in hoop skirts made of giant candy canes, gingerbread men and cupcakes.

Yet Carey’s own over-the-top holiday sheen stole the show as she emerged on stage 40 minutes late, with fans madly flinging their phones and selfie sticks into the air chanting, “Mariah! Mariah!”

Dripping in diamonds and decked out in a red satin gown with a pink sash by designer Anna Maier, the pop diva kicked off the night singing “Here Comes Santa Claus.”

“I wrote this song a long time ago,” said Carey as she introduced “All I Want for Christmas Is You,” which was first released in 1994 as the lead single from her first holiday album, “Merry Christmas.”

The song later got a revival in 2003 thanks to the release of the Christmas rom-com “Love Actually,” where Carey’s big holiday classic was belted out by a young Olivia Olson.

With fireworks and confetti raining down on fans, Carey waved to the crowd throughout her Toronto performance — which lasted little more than five minutes.

According to TMZ, Carey reportedly raked in a cool $1 million for her short yet sweet Toronto appearance.