Kourtney Kardashian met up with her ex-hookup Justin Bieber and his wife Hailey Baldwin at the studio yesterday and we're REALLY wondering why! How AWKWARD!

The mother-of-three was dressed down for the meeting with the world's most famous couple at Milk Studios, on Monday. What the heck kinda collab could this trio be doing?!

And as awkward as it may be for Hailey to be present while her hubby meets up with his ex, she can be assured that Kourt isn't gonna put the moves on her man because KK's still hooking up with her other ex Younes Bendjima, according to a new report. Apparently the two are friends with benefits since Kourtney cooled on the previously serious relationship -- now she just wants some sexy fun! "He’s [Younes] head over heels and would get serious again in a heartbeat, but Kourt’s no longer there at the moment and just wants to keep things casual," according to Radar Online.

And this wouldn't be the first Kardashian-Bieber collab -- the other day, at Justin's charity even for LIFT Los Angeles and Inner-City Arts, Kylie Jenner dueted with Justin on her infamous one-liner song "Rise and Shine!"