What we wouldn't give to be a fly on the wall of this shindig!

Justin Bieber had a huge night at the Grammys on Sunday, winning his first award and performing with Skrillex, and he feted his accomplishments with an after party at his fave spot The Nice Guy. Kourtney and Khloe Kardashian attended, and we have a feeling the eldest K sister is still doing the bone dance with The Biebs!

Hailey Baldwin was nowhere in sight, and neither were Kourt's sisters Kendall and Kylie, who are actually friends with the Canadian crooner. We still can't believe JB would be into the mother-of-three, but allegedly he has a thing for older women. One person who can't love this pairing is Scott Disick, who reportedly is trying to win back his baby mama.

We guess it wasn't too late for Justin to say sorry to Kourtney for hitting it and quitting it!