The Hollywood star - famous for roles in The Fresh Prince of Bel-Air and Men in Black - met students at St Martin-in-the-Fields High School for Girls in Tulse Hill, doing a question and answer session and signing autographs.
More top news
Chris Gard and Connie Yates want their nine-month-old son Charlie to undergo a therapy trial in the US.
Labour leader Jeremy Corbyn was unable to provide the cost of his party's key manifesto plans on free child care.
Montana Abdhou was with a group of friends when two men on bikes opened fire.