Taking to Instagram Monday night, the powerhouse singer shared a short clip of herself dressed up in a fitted black onesie, with thigh-high lace-up boots and a witch's hat riding a stationary bike in front of a spooky forest background filled with jack-o'-lanterns.
As the camera zooms in, she lets out a witch's cackle before the scene changes to Mariah dressed in a red onesie with white trim.
"It's Time," she sings as the camera zooms out to show her on a reindeer as snow falls and her song "All I Want For Christmas" plays in the background.
MORE: Mariah Carey announces 'Merry Christmas to All!' shows"IT’S TIIIIIIIIME!!!!!!!!," the icon captioned the clip along with the Christmas tree, party hat and red heart emojis and #MariahSZN.
Mariah also marked the location of the post as "It's Time!"