Kate, wearing a camel jacket and trousers, met with frontline staff and young people at Streets of Growth in Aldgate.
She said she was keen to “connect the dots” with her work on early childhood, and stressed the need to meet with families and young people “before it gets to crisis point”.
The charity, established in 2001, specialises in targeted outreach and intervention to re-engage young people aged 15 to 25 at risk of isolation, exploitation, violence and crime.
Kate was greeted by Streets of Growth founder Darren Way and spoke of her admiration for large communal spaces and “places where everyone can come together to be creative – it’s really precious”.
She then spoke to eight workers from the charity about whether a stigma still existed around mental health, and the needs of young people today.
The princess said an effort must be made to understand the people as individuals, before adding: “I love the fact that you’re going out into communities.”
Kate then met two sets of mothers and daughters to speak about the support they have received, and how she thought the charity offered “something that young people are craving”.
The families also showed her jewellery and footwear designs made possible by Streets of Growth’s creative workshops, which the princess described as “really beautiful” and “so creative”.
She joined three young people engaged in a mental health session styled as a podcast, with topics including social media and body image under discussion.
A worker posed for a selfie with the princess before she met trustees and patrons of the charity, including actor Eddie Marsan, who told Kate he “wanted to give something back” through his support.
Streets of Growth, with its aim to transform the lives of young people at risk of becoming “seriously stuck” in a cycle of isolation, exploitation, violence and crime, has so far helped more than 5,000 young people.
Its founding was inspired by a research visit to see the work of urban violence prevention charity Roca in Boston, which Kate and her husband the Prince of Wales themselves visited during their time in the US city in December last year.
Speaking after the visit, Mr Way said: “This is a very unusual approach to mental health by taking talks to the street.
“We’re going out to gangs and non-gangs (and) we go in your house to help young people escape domestic violence.”
Mr Way admitted funding in the sector was scarce but remained bullish about its outlook, adding: “When you get an organisation like us that was founded with £10 and two chairs… to 22 years later Her Royal Highness recognising our work, the sky’s the limit now – it’s game on.”