Smith had the crowd on its feet as he rocked the microphone. All that was missing was DJ Jazzy Jeff.
Also during the commercial break, the 46-year-old actor took the crowd back to Bel-Air, launching into the intro to his hit '90s sitcom "The Fresh Prince of Bel-Air."
But instead of rapping the whole thing, Smith let the audience fill in the gaps. It didn't quite pass the test, but it was all good fun.
You can check out the video on the "Ellen" website.