Metallica's first Irish show in a decade kicks off this evening at Slane with an estimated 75,000 fans expected to attend.
The band have arrived and have been spotted out and about at their Dublin Merrion hotel, with massive crowds already making their way to Co Meath for the concert which is part of Metallica's European Tour.
Met Eireann have warned fans to don the brollies and come well prepared for the weather. Rain showers are expected before the band takes the stage, but there is hope it will be dry by the time the concert begins.
They said: "Scattered outbreaks of rain in parts of the north east will die out this morning.
"Otherwise bright with scattered showers in the west and southwest becoming more widespread this afternoon but some good sunny spells too. Highest temperatures 13 to 16 degrees."
Promotors MCD have said there will be searches when entering the premises and a list of prohibited items and information needed is available here. They also appealed to fans to respect the local community by not littering, not engaging in anti-social behaviour and by not parking illegally.
Slane's Lord Henry Mountcharles says it's not just Irish people who will be attending:
"There is a high attendance from overseas which is of the highest attendance from overseas with the widest geographical spread. I think it's correct we have someone from Chile going."
He also urged people to steer clear of the River Boyne and to respect people's homes and property in Slane village:
"Please, please, keep away from the River Boyne. It looks very attractive, it's a wonderful river, people sing about it, but don't swim in it. It is a hungry river and it's dangerous."
Fans are being asked to arrive to the concert via public transport and have been advised to book in advance.
AA Roadwatch and Chief Superintendent Ferguson Healy had this advice for fans driving to the concert:
"We are expecting a lot of traffic so we have a robust traffic plan in place to deal with those issues. Each of the carparks are colour coded to assist people. The one thing I would say is that when you do park in a car park, please rememeber the colour code of the car park that you left and went to the venue from."
While Metallica don't take to the stage until 8pm, many fans have already set up to watch Fangclub. Bokassa, Stiff Little Fingers and Ghost.