Rugby fans will be handed megaphones on Saturday in an official bid to record "the loudest roar in the world" at Saturday's Five Nations championship match between Ireland and Scotland.
Around 15,000 megaphones will be distributed by Guinness to the 50,000 supporters streaming into Lansdowne Road stadium.
A spokesman said: "Environmental engineers have been employed to record the roar, and they will be closely observed by an official from the Guinness Book of Records to ensure that all rules and regulations are followed.
"The decibel level will be measured throughout the match, with the loudest roar of the afternoon submitted."
Vanessa Law, of the Guinness Book of Records, said: "This is an attempt to create a new category, and we hope to be able to ratify it as a record when the documentation has been studied."
Irish team captain Keith Wood commented: "It's always fantastic to play in front of a home crowd. Scotland won't know what hit them when the Irish fans roar for us through their megaphones."