DeMar DeRozan, Russ Westbrook Dance On Stage With Kendrick Lamar, LeBron In Crowd

Kendrick Lamar's "Pop Out" concert in L.A. looked something like NBA All-Star Weekend ... with LeBron James, Russell Westbrook, DeMar DeRozan and James Harden all attending the massive event -- and two of the superstar ballers even hopped onstage!!

K. Dot set the world on fire during his Juneteenth unity celebration at the Kia Forum on Wednesday ... where he performed his iconic Drake disses for the first time, as well as all the classics from his discography.

Bron, Russ, DeMar and Harden were all present for the epic night of music ... and when the time came for Kendrick to perform "Not Like Us" (several times in a row, mind you), Westbrook and DeRozan were right by his side -- as well as DJ Mustard, who produced the scathing track.

It was no surprise to see Brodie hop up on the platform to support Lamar, considering his California roots ... but DeRozan's appearance could be viewed as a declaration of his allegiance to Kendrick over Drake amid their beef, as he has ties to both Compton and the Toronto Raptors -- Drizzy's hometown team.

Bron and Harden remained in the crowd throughout the night ... but it's clear they were loving every second -- rapping along and vibing to Lamar's tracks.

Countless other VIPs also hit up the venue for the show ... and a handful of others also joined Lamar onstage.

Westbrook went to Instagram to weigh in on the experience ... saying, "IF YOU KNOW YOU KNOW!!! REAL WESTSIDE S***"