Flau'jae Johnson's doing way more than hooping in arenas now ... 'cause the LSU star and rapper performed in front of a huge crowd at Rod Wave's concert in Atlanta -- and the fans loved it!
The Tigers guard -- who's got some downtime before LSU's next game on Dec. 17 -- was front and center at Rod's "Nostalgia" tour alongside Ari Lennox, Toosi, G Herbo and Eelmatic.
Several fans immediately recognized the 2023 NCAA champ when she took the stage ... and captured footage of her performance of her hit song, "Big 4.