Amy Winehouse will return to the V Festival later, a year after cancelling her appearance at the event.
The singer joins a host of acts, including The Verve and Kings Of Leon, who will perform at the festival, which takes place this weekend in Chelmsford and Staffordshire.
Other bands due to perform include Muse, Duffy and Kaiser Chiefs
But people going to the Staffordshire event have been warned not to go without a genuine ticket.
Brandon Cook from Trading Standards said undercover officers will be working with police to find ticket touts at the Weston Park site.
He said they would also be searching for counterfeit goods at stalls and around car park areas.
Police have warned of road congestion as about 90,000 people attend the two-day event.
Most of the festival goers are camping, and the site opened on Thursday this year, a day earlier than usual, in a bid to avoid traffic problems which were seen last year.
Mr Cook said: "We will be working closely with the police to locate touts and check what they are selling - we don't want people ripped off.
"If you haven't got a genuine ticket the message really is 'I'm afraid you've missed out and watch it on the telly'."
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