Shaq Beatboxes For Drake ... Let's Do 'Back to Back'

Shaq got Drake to rap "Back to Back" on live TV Sunday night while the Big Fella provided the beat ... and it's just as awesome as it sounds.

The two were on "Inside the NBA" with the rest of the crew when they asked Drake to do a little live rap on the air.

Drake tried to launch into a freestyle ... but Shaq quickly corrected him -- "No, the original."

Drake obliged ... and did the verse.