Boris Johnson strummed a guitar at London Bridge Station on Tuesday morning to launch the Mayor of London's annual talent competition.
The Mayor was joined by former busker Misha B and Josh Osho, a young South London singer-songwriter.
The 'Gigs 2013' competition gives musicians the opportunity to perform at landmark locations around London and compete for a host of music prizes including a coveted official London Underground busking licence and studio recording time.
Boris Johnson said: "It is surprising how many stars started their careers busking – from Simon and Garfunkel to Tracy Chapman. This is the perfect opportunity for our talented young musicians to show off their skills and win prizes that could help launch their careers."
Misha B said: "Busking played such an important part at the beginning of my career, I'm really pleased and proud to be supporting this initiative."
The competition is open to Londoners aged 11 to 25 who can sign up at www.gigsbigbusk.com