11:23 AM PT -- Sources with direct knowledge tell TMZ ... Kim and Peter are just friends, and they just so happened to be sitting next to each other at the game. So ... no funny business.

Kim Kardashian reunited with a guy who used to hang out with her and her ex-husband Kris Humphries -- and even all this time later ... they look real friendly, especially courtside.

The reality star went to the Lakers game in L.A. Tuesday night with her daughter, North, and some pals -- and yes ... she had a front-row seat to all the action ... as did basketball player-turned-real-estate-agent Peter Cornell, who was plopped down next to Kim at one point.

They were photographed chatting it up and flashing big smiles as they watched the game seated next to Will Ferrell ... and it's interesting considering their history. If you didn't know, these two go way back.

Pete -- who also used to play basketball in the 2000s -- used to hang out with Kris a whole lot while he was briefly married to Kim K ... and he even served as a groomsman during their wedding in 2011.

There are shots of Pete and Kris (and Kim) rolling together as a crew at the time as well ... so yeah, he definitely knows KK -- and they're clearly still on very good terms in 2024.

Unclear if Kim and Pete hang out a whole bunch these days -- but at least for this run-in, they were chummy and cordial ... certainly enough so to chop it up as publicly as they did here. Since Kim divorced Kris, we haven't really seen the two dudes hang out very much.

They were good buddies in the 2010s ... but at this point, there's no evidence they stay in touch -- in fact, they don't even follow each other on Instagram. So, there you go.

Kim, of course, has done a lot since her time with Kris ... having married and divorced Kanye West -- not to mention welcoming four different children with him too. She's also amassed an impressive empire for herself outside of TV ... so they've come a long way since.

Pete -- who actually helped Kim and Kris buy their first crib together post-wedding -- has continued to work in the real estate biz ... he actually works for The Oppenheim Group, and has become a bit of a reality star himself thanks to "Selling Sunset," etc.

Nothing like a good catch-up!