More than 50 musicians are competing online for an official busking slot on London's Underground.
Last month 52 buskers were filmed performing at Tube stations. Their film clips have been put online for a public vote to select the 20 most popular.
Judges will select 10 finalists for a live "busk-off" in September, with the three winners gaining a year's licence to busk on the Underground.
One winner will also receive a bass guitar signed by pop star Sting.
The Busking Underground contest was launched as part of London Mayor Boris Johnson's Rhythm of London events series.
Competitors include duo Sam Quill and Niki Chang, who performed the song Russian Thunder outside Liverpool Street station, and Renato Vanzella who performed Beatles song Can't Buy Me Love outside Embankment station.
The online vote ends on 31 August.
The 10 finalists will perform at Young People's Question Time at the 02 in Greenwich, east London, on 17 September.
Transport for London took over management of the Tube's busking pitches last year.