Members of indie rock outfit The Kooks left police reeling after plans to stage a gig in a busy shopping street were kept secret until the last minute.
One half of the internationally renowned Brighton band are to perform an acoustic set for a live radio show in Hove on Friday, when George Street's Christmas lights are switched on.
But Sussex police were only told of the performance yesterday, giving officers little time to plan for the event.
It sparked fears for crowd control should hundreds of fans turn up wanting to catch a glimpse of their idols.
Brighton and Hove City Council was also left in the dark about the details of the show. The council's licensing department received a phone call yesterday morning from organisers who asked for permission to put a band on in George Street.
The request was refused and organisers were told that by law they needed to give the council ten days' notice and the police 48 hours' notice.
Instead, organisers decided to stage the show by two members of The Kooks on a much smaller scale inside the Slug and Lettuce pub in George Street, which has its own entertainment licence.
If they had applied for the temporary event notice in time, a crowd of up to 500 people would have been allowed into the street.
The event has been organised by Hove Business Association and Brighton and Hove Business Forum in conjunction with Juice FM, which will broadcast the concert to its listeners.
George Street has staged many shows to mark the switching on of the Christmas lights but organisers are toasting their success at securing such a major music name.
Gavin Stewart, Hove Town Centre Manager, said: "This event proves that Hove really is the place to be.
"There is a real buzz of excitement about what businesses can achieve if we all work together. If Hove can follow Brighton's lead by creating a Business Improvement District, this is just a taster of things to come."
Mr Stewart made details of the gig public yesterday in a Press release but police said it was the first they had heard.
Initially, some feared it would be a repeat of a show by indie rockers Razorlight, who staged a secret gig on the seafront in the summer, but without any of the planning with council officers and police which went into that show.
However, Andy Walker, from the Hove Business Association Committee, played down the scale of The Kooks' performance.
He said only two band members, not including singer Luke Pritchard, would be present while the rest of the band play in France.
Unlike the Razorlight show, which attracted thousands of invited guests on the seafront, this time only 100 people will be allowed into the pub for the gig.
A police spokeswoman said there would be extra policing in George Street on Friday. She said: "We would have liked a lot more time."