Some 80,000 Red Hot Chili Peppers fans will make their way to Co Meath today to watch the US group perform at the annual Slane Castle gig.
Anyone hoping to gain last minute access has little chance. Tickets for today's event, at €59.50 each, were snapped up by Irish fans in just under two and a half hours when they went on sale in March.
While Robbie Williams played to a bigger crowd, of 135,000, at his show in Dublin's Phoenix Park earlier this month, today's gig is one for the more serious rockers. The Chilis, as they are known, have a live pedigree which is perhaps rivalled only by our own U2.
They have been voted Best Live Band in the World by MTV viewers, Best Live Act by Hot Press readers, Best International Band at the Brit Awards and Best International Live Band at the Meteor Ireland Music Awards.
In between collecting gongs at international award ceremonies, the Chilis have sold 25 million albums worldwide.
They opted to return to Slane following the phenomenal reaction they received from Irish fans when they supported U2 at Slane 2001.
Hits such as Under The Bridge, Californication, Around The Round, Can't Stop and By The Way are all likely to feature on the play list when their set starts at around 8.30 p.m.
Doors open at 11 a.m. and Halite, the first of six warm-up acts, kicks off proceedings at 12 noon. They are followed by Morcheeba, Feeder, P.J. Harvey, Queens of the Stone Age and Foo Fighters.
The Irish Red Cross (IRC) has warned those attending the gig to avoid excessive drinking before the event.
The IRC is concerned the price of alcohol, at €5 per pint inside the venue, may encourage some concert-goers to consume as much as they can before entering the Slane Castle site.
Mr Liam Collins, IRC Dublin south director of units, said he has witnessed first-hand the effects of excessive drinking at outdoor summer concerts.
"If they're young they might decide to drink before they come in. Then they come in and sit down in the heat and fall asleep. What happens is they can get dehydrated and sunburned, they don't even think of drinking water." He added the likelihood of widespread crowd safety problems would depend on the age profile of the crowd. At the recent Robbie Williams concert, while the crowd was "well behaved and well prepared", many encountered difficulties.
"There were many requests for sunburn treatment. Demand was also high for water and for treatment for wasp stings."
The IRC has urged those attending to prepare properly.
Bring additional clothes. Even if it is warm at the start of the day, temperatures drop as the sun sets.
Bring waterproof clothing, preferably something big enough to sit on.
Wear sun protection and bring plenty of sun screen with you. Hats should also be used as protection from the sun.
Designate a meeting place at the venue. Don't rely on mobile phones, which may not work because of huge demands on networks.
People with pre-existing conditions such as asthma, epilepsy and diabetes are advised to wear medical bracelets.
Wear comfortable shoes and eat something substantial before leaving home.
