Kevin Hart and Usher Bro Down at Vegas Pool Party

Kevin Hart and Usher were hangin' in Vegas Saturday after Kev's Hart Beat Charity Concert.

Kevin and Usher hosted the TAO Pool Party at the Venetian. It's gotta feel good for Usher, after getting socked with 4 lawsuits claiming he exposed several individuals to genital herpes.

The charity event benefited children diagnosed with cancer. Check out the video below ... Kevin busted some serious moves with his wife, Eniko.