Mariah Carey celebrates. Beyoncé celebrates. Everyone's happy.

Week long festivities
The celebrations continued on for Mariah Carey. She spent the day celebrating her historic 19th number one with fans, as well as with her kids Rocky and Monroe.

That was after she lit up the Empire State Building this week, and offered up a rare televised performance of ‘Oh Santa’ during a visit to ‘The Late Late Show With James Corden.’ The original festive cut is lifted off her 2010 project, ‘Merry Christmas II You.’

It was a cute performance, with the little kids dancing around and Mariah serving up some dolphin whistles here and there. It also looked like the performance took place on the same night she wrapped up her 6th Annual 'All I Want for Christmas Is You'  concerts at Madison Square Garden on Sunday. This YouTube channel has been uploading some really amazing video footage from that last show if you're interested in viewing the concert.

Here's a video they posted of her kids performing 'Rudolph The Red Nosed Reindeer':
Cute.

Beyoncé and her mom Tina Lawson (alongside Kelly Rowland) attended a big Hollywood karaoke Christmas party on Tuesday night:
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The party was hosted by celebrity jeweler Lorraine Schwartz and her sister Ofira Sandberg at the Blind Dragon in Los Angeles. Schwartz and Sandberg performed Mariah’s 'All I Want for Christmas Is You' — along with Beyoncé and other party guests dancing and singing along. Bey and Mariah are good friends. Bey would have been ecstatic for MC.

Here's some video footage of Bey at the event:
Doesn't seem Jay Z was there to snatch any phones. I see she brought back her 'Lemonade' braids. Love it. Hopefully, we get some video footage of said performance. At least we don't have to wait long for the new 'All I Want for Christmas Is You' music video, which premieres later tonight.