Max is back by special request from the Welsh camp, who want the whole occasion at the Millennium Stadium to have a true Welsh rugby feel about it. As well as working at the 1999 World Cup, Max was also famously out in the middle urging on the fans ahead of the memorable victory over England at Wembley in the same year.
Six years on the most famous son of Glynneath is hoping for a repeat victory against the Irish to secure a first Grand Slam since 1978.
"The team approached me after my Wales Millennium Centre performance and said it would be great if I could sing before the England game. Unfortunately, I couldnt do it," said an excited Max.
"But when the team management approached me at Murrayfield with the same request for this game, I was delighted. They said they wanted to create the greatest possible atmosphere for the team.
"Ive had to cancel everything to write these verses in 24 hours but I really hope the crowd will get into the Millennium Stadium early to make it a day no-one will forget. Leave the beer behind and come and have a good old sing-song before kick-off.
"It will be like recreating the atmosphere at Wembley - only better because we are in Cardiff this time."
Max will be joining Katherine Jenkins and Charlotte Church to sing the National Anthem - "I have never sung Hen Wlad fy Nhadau at a Wales match before so Im sure that will be fantastic. Its going to be a unique occasion that the crowd can play an important part in."
Katherine and Max have already performed twice together - Max invited Katherine to perform at his Sydney Opera House concert during Rugby World Cup 2003 - and they both sang at the Wales Millennium Centres opening concerts.
"Its also great to be playing at a Wales v Ireland match because I love playing to Irish audiences - almost as much as I love performing in Wales," added Max.
Wales team manager Alan Phillips said: "The singing from the Welsh fans at the matches at both the Millennium Stadium and away from home has been a major factor in our success story so far. It is back to the good old days when people used to say the Cardiff crowd was worth seven points to the home side.
"The crowd were in early for the game against England and Michael Owen and his players are hoping to see a near full house when they come out for their warm-up an hour before kick-off. It really makes a difference to hear the encouragement at that stage."