It might be cold outside, but Mariah Carey sure knows how to heat things up.

The “We Belong Together” singer took to Instagram on Sunday to share photo of herself in a plunging gold one-piece bathing suit, standing knee deep in a hot tub -- while completely surrounded by snow.

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Carey looked amazing (and freezing) in the photo that showed off her slim figure, captioning the pic: “#traditions #aspen #wintermoments Sending love to all my #lambs.”

The 45-year-old performer spent her Christmas weekend with her ex, Nick Cannon, and their twins, Moroccan and Monroe, 4. The famous exes seem to have the holiday co-parenting thing down to a science, even spending Thanksgiving together this year.

Santa Claus also stopped by on Christmas Eve to drop off presents for her children, and of course pose for a couple of Instagram photos.

In another photo, Carey -- wearing a Hello Kitty onesie -- took a seat on Santa’s lap.

“#meandmyfriendsanta. I know him!!! " she captioned the picture, giving a nod to the holiday film Elf.

WATCH: Mariah Carey and Nick Cannon Couldn't Look Happier Together in Adorable Family Photo

Did we mention that Santa arrived on a sleigh to their Aspen vacation spot with real reindeer?!

Kris Kringle wasn’t the only special guy to visit during the holidays. Carey's new boyfriend, James Packer, was in town earlier in the week. Watch the video below to see how she met her billion beau.