LL Cool J, Flavor Flav and Busta Rhymes Rapping Along Backstage at Grammys

The Grammys' hip hop tribute to celebrate the culture's 50th anniversary stole the show -- and even had some legends nodding their heads and rapping along while waiting in the wings backstage.

TMZ Hip Hop obtained this video of LL Cool J rappin' out to Too Short's "Blow The Whistle" and The LOX's "We Gon Make It" in between takes of his own "I Can't Live Without My Radio."

Busta Rhymes, Spliff Star, Run-DMC and Flavor Flav all performed their own classic tunes too, and also couldn't contain their excitement while waiting to get onstage for the grand finale ... where ALL of the artists came out at the same time.

This coming August will mark 50 years since DJ Kool Herc birthed hip hop with a party in the Bronx, and the Grammys put the anniversary spotlight on a ton of famous faces -- Black Thought of the Roots, Grandmaster Flash & the Furious Five, DJ Jazzy Jeff, Salt-N-Pepa, Rakim, Chuck D and Flav for Public Enemy, Posdonous for De La Soul, Scarface, Ice-T, Queen Latifah, Method Man for Wu-Tang Clan, Big Boi for Outkast, Missy Elliott, Nelly, DJ Drama, Lil Baby, GloRilla and Lil Uzi Vert (with his new Philly Eagles anthem) all contributed to the performance!!!