Will Smith may have spent the better part of two decades moving on from his Fresh Prince of Bel-Air roots, but he hasn't forgotten the show's theme song.

The rapper-turned-actor took viewers of British talk show The Graham Norton Show down memory lane when he performed an impromptu version of the show's iconic theme song.

Smith is currently promoting the third installment of the Men In Black franchise, but conceded if it wasn't for the original sitcom, he'd be nowhere.

Every country in the world, that is the thing that I am most known for, he said. No matter how big the movies get, it's the 'Fresh Prince' everywhere. As long as they are screaming Will, I'm cool... It is so funny that so many people recognize that theme song.

The show's host Graham Norton called Smith's bluff and whipped out a keyboard and pre-programmed beat. Smith ran through the theme song in its entirety, with some raucous audience participation.

Smith already made news today, after slapping Russian reporter Vitalii Sediuk on the red carpet at the Moscow premiere of Men In Black III.

Check out Smith's performance of the theme song below: