The 44-year-old actor is currently in the UK capital with his son Jaden, who is opening for Justin Bieber on his 'Believe' tour, and was shown around by local politicians Tessa Jowell and Chuka Umunna, reported the Daily Star.
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 female pupils.
The actor hosted a question-and-answer session with the girls and offered up advice on breaking into the entertainment industry.
"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," she added.
Jowell said the visit was organised after Smith expressed a desire to see "London's Harlem" in reference to the New York City neighbourhood.