As many as 250,000 revellers are expected to brave rainy forecasts at V Festival this weekend to celebrate the rock and pop showcase's 20th anniversary.
Scottish DJ Calvin Harris and rockers Kasabian will headline the festival's two sites at Hylands Park in Essex and Weston Park in Staffordshire.
Organisers say a quarter of a million guests will pack out the fields as a rich variety of British talent populates the remainder of the two-day line-up, including Sam Smith, Stereophonics, Olly Murs, Tom Jones and Paloma Faith.
Faith, who was recently announced as Rita Ora's replacement on talent show The Voice, tweeted: "Who is coming to see me at @vfestival ? I am very excited cause I'm in a big tent and I LOVE A BIG TENT ME!!!!"
Complementing the weekend's music will be a number of performances by comedians, such as Frankie Boyle and Russell Kane.
But the late-summer festival fever could be tempered by dampness and mud, as rain is forecast throughout the weekend at Staffordshire and on Sunday in Essex.
Sunnier prospects for Hylands Park on Saturday means festival-goers should be equipped with both sunglasses and waterproofs, with temperatures reaching 28 degrees Celsius, according to the Met Office.
Tackling drug abuse at the weekender will be a top priority for police, after three people suffered "serious side-effects" from taking ecstasy-style tablets at last year's event.
Staffordshire Police Superintendent Elliott Sharrard-Williams said: "Drugs and legal highs are not welcome at V. If you take them, or attempt to sell them, you will be caught and dealt with."
Essex Police also tweeted a picture of sniffer dog Orla, who will be one of four dogs operating on site at Chelmsford.
Chief Inspector Jon Hayter said: "Don't be alarmed if they sniff around you, they are just doing their job."