Karlie was hosting a party for her new single, "Ferrari Karlie," at Atlanta club Buckethead Loft when her now soon-to-be husband got down on bended knee and proposed. The pair has only been dating for few months -- he's her first relationship since she split with Grammy-nominated producer Sean Garrett.

There's not a whole lot of info available about Redd's new man ... but his name is apparently Mo, and he goes by Arkansas Mo on Instagram.

Karlie seemed a little more interested in the box the ring came in at first. It's pretty cool ... it displayed a bunch of pictures on an LED screen when she opened it. Her ring ain't too shabby either.