The pair were visiting Reprezent FM in Brixton, south London, a youth-orientated radio station set up 10 years ago in response to the rise in knife crime.
Among the well-wishers waiting to meet the couple in the crowd, Francine told Sky News: "I hope that Prince Harry coming here will help the crime in Brixton, and that he will work with youths here."
Local resident Inna said Meghan was an inspiration for her daughters Davinna and Veronique - "a mixed race girl becoming a princess in the Royal Family".
Young Davinna even painted a picture of two pink flamingos forming a heart with their bodies to give to Meghan.
Karen, from Kennington, told Sky News she was there because Harry was "a people's Prince, he loves Jamaica and I'm Jamaican... I'm so happy he's marrying such sparkling young lady".
After raising eyebrows with the eyewatering cost of the couture dress she wore in her engagement portraits with Prince Harry (£56,000), at least part of her wardrobe was a little more affordable this time round with a black jumper by Marks & Spencer.
The couple spent half an hour speaking to the presenters and volunteers at Reprezent radio station, which is based in Pop Brixton - a community project housing local businesses and start-ups inside shipping containers.
The initiative has helped more than 4,000 young people, offering accredited training and teaching employment skills through music, radio and media.
While speaking to the station's youngest DJ, 17-year-old Glory, Harry made Meghan laugh by gesturing towards a CD player as if he was about to start "scratching" a track.
Meghan told Glory: "I can see why your show is so popular. You're so thoughtful and your approach is so engaging."
She added: "I must tune in."
Station founder Shane Carey said that since the Royal visit had been announced, the not-for-profit station was "having the spotlight shone on us from all the world's media pretty much, we've never had this attention".
This was Harry and Meghan's second official outing since the announcement of their engagement in November.
The first was to a youth project and World AIDS Day event in Nottingham at the start of December.
Harry and Meghan are set to wed on 19 May at in the medieval castle's chapel at Windsor Castle.
With just five months to go, the local authority has faced criticism for their attempt to remove the homeless from Windsor's streets in preparation for the Royal wedding.