Los Angeles party promoter Sincere Show recently hosted a huge bash for Hip-Hop royalty, as Diddy's son Justin Combs celebrated his 21st birthday in the Hollywood Hills with celebs like French Montana, Khloe Kardashian, Justin Bieber, Kendall Jenner, and of course, Diddy.

Check out the above behind-the-scenes look at the '90s themed affair, where guests dressed up in their classic Hip-Hop garb and danced the night away to Bad Boy classics from Mase, 112, G-Dep, Black Rob and more.