The Independence Day star is currently in the capital with his son Jaden, who is opening for Justin Bieber on his Believe tour, and was shown around Brixton by local politicians Tessa Jowell and Chuka Umunna.
Jowell revealed the visit was organised after Smith expressed a desire to see "London's Harlem" in reference to the New York City neighbourhood.
During his day out, Smith visited local music venue Electric Brixton and a coffee shop, before stopping by St Martin's School in Tulse Hill where he was given a rapturous welcome by 950 unsuspecting female pupils.
The actor/rapper hosted a question-and-answer session with the girls and offered up advice on breaking into the entertainment industry.
Headmistress Lesley Morrison says, "He was fantastic, he spoke with such sincerity, really aspirational, it was a truly inspirational visit the girls will never forget. I know that he's a superstar and everything but he is a humble man as well.
"The girls will never ever forget it... I wasn't quite sure how they would react but they were just totally and utterly thrilled. They've all watched (Smith's TV show) The Fresh Prince of Bel-Air but they've seen all the Men In Black films as well."