Rock band The View chose an unsigned three-piece group to support them at a gig in Norwich - just hours before the Friday concert began.
Tickets for The View's tour sold out in 45 minutes
Local group Monroes were picked after the Dundee-based band launched an urgent appeal to find new talent after their support band dropped out.
The idea was inspired by The View's big break, when they handed a demo to Babyshambles frontman Pete Doherty.
Monroes drummer Lenny Rout said he was "nervous and excited".
The group, made up of three 18-year-old students, have been together for two years and have performed in and around Norwich.
Rout likens their sound to "indie new wave with ska and reggae influences".
Norwich-based band Monroes have been together for two years
During Friday, The View put out an urgent appeal for interested bands to drop off demo tapes at their tour bus at the University of East Anglia, where the gig was staged.
Before the decision was made, The View's guitarist Peter Reilly told the BBC News website: "We thought it would be a good idea to give them a chance.
"Because we knocked on Doherty's tour bus, and he gave us a chance, it's kind of returning the favour."
Reilly said the band planned to search for more unsigned talent in the future.
"It's good to give a band a chance. There's always room to fit a band on your bill," he said.
The band listened to more than 50 demo tapes before picking their favourite.
Manager Grant Dickson said he was "blown away" by the response, saying he was "amazingly surprised at how many good bands are around".
The View have enjoyed huge success with their brand of guitar rock since their debut album, Hats Off to the Buskers, topped the chart following its release in January.
Last month they launched a public appeal for lookalikes to take part in a music video.
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