GAA supporters and concert goers have been banned from bringing large bags and backpacks into Croke Park.
The new rule comes into effect as and from this Sunday, June 25, and has been announced just a couple of weeks after the Aviva Stadium brought in similar security measures.
The ban will impact on Dublin supporters heading to Croker for Sunday's Leinster Senior Football Championship semi-final against Westmeath.
In a statement released today, Croke Park say that smaller bags are allowed but will be subject to a search.
"Following a review of safety procedures with the relevant statutory authorities, Croke Park can confirm that as of Sunday, 25 June 2017, patrons will not be permitted to take large bags and backpacks into the stadium for all match day and concert events.
"Smaller bags will be permitted but may be subject to searches and patrons are urged not to bring bags at all where possible.
"We would like to thank our patrons in advance for their cooperation with this matter as we look forward to a fantastic season of concerts and matches in Croke Park over the coming months."
As well as all the usual summer sporting action, GAA HQ is also set to stage two massive music concerts with both U2, on July 8, and Coldplay on July 22.
For further info, people are asked to check out the FAQ section on the Croke Park website.