Even Santa Claus, bedecked in Leinster blue, has been advised to get there early to avoid the squeeze generated by another massive demonstration of people power.
The Pied Piper has nothing on the defending champions, even without headline acts like Brian O'Driscoll and Rob Kearney.
Whatever the precise final figure, the crowd will be the largest for any match during any season of the pool competition anywhere in Ireland, topping the 46,400 Leinster packed in on the corresponding Saturday last year when they responded by giving Bath a fearful run-around.
Should the holders fail to avenge the near miss in France last week, it won't be for any lack of support. In what has become an annual visit over the last three seasons, Clermont have always found Leinster in Dublin beyond their reach, if only just.
They lost there 12-9 ten years ago and 24-8 last season. The narrowest squeak of all came in between, a quarter-final two seasons back when Clermont lost 29-28 at the end of a staggering 80 minutes during which their Australian stand-off, Brock James, missed enough kicks to last him all season.
This time Leinster need to make home support count to ensure they take their customary place in the last eight. Clermont, five points clear after maximum wins over the Scarlets and Exeter, complete the pool stage in the New Year at home to the Chiefs followed by a trip to Llanelli.
Leinster, who finish up with matches against the same opponents but with the venues the other way round, dare not lose on Saturday if they are to make theirs the longest reign in European history by extending it to the knock-out stage.
Leicester, the only other club to win back-to-back titles, failed to get that far the season after beating Munster in Cardiff in 2002.
In the best of all Leinster worlds, a 5-0 split of the points on offer at the weekend would give them control of the pool.
The problem with that is not so much that the champions have managed just the one try in three European ties but that Clermont are not in the habit of conceding four in one match.
They have done so in the Top 14 only three times in three seasons - at Montpellier in February 2010, Stade Francais in Paris the following November and at home to Perpignan in September, a match which they won at a canter by scoring seven of their own.
In the course of ending Leinster's 17-match unbeaten European run last Sunday, Clermont surely set a competition record for multi-nationalism.
The 15-12 home win, their 51st on the trot at the Stade Marcel Michelin, involved players from 11 countries - Australia (Brock James), Canada (Jamie Cudmore), Fiji (Napolioni Nalaga), Georgia (Davit Zirakashvili), New Zealand (Sitiveni Sivivatu), Portugal (Julien Bardy), Samoa (Ti'I Paulo), Scotland (Nathan Hines), South Africa (Daniel Kotze), Wales (Lee Byrne) and of course France.
Leinster's is not the only major Irish event on Saturday involving a club from the RaboDirect PRO12. The other kicks off a little later across the border in Belfast where Ulster intend to start against Northampton where they finished in the English town last Friday night.
The crowd at Ravenhill will be rather modest compared to Dublin but the passion will be every bit as great. Ulster, 13 wins from 13 matches this season, know a 14th will keep them on track for a home quarter-final. Not for nothing are they the team of the season do date.
Turning what was supposed to have been a close contest into a mighty statement of intent at Franklin's Gardens, made theirs the performance of the weekend, a five-pointer showing an English audience why Ulster lead the RaboDirect PRO12.
Connacht finished hot on their heels, a 22-14 home win over Biarritz providing further incontrovertible evidence that Ireland's western province are not there simply to make up the numbers.
A victory achieved without the customary wind and rain blowing in off the Atlantic reinforces Connacht's belief that they can do the double when they cross the Bay of Biscay for Friday night's return.
Biarritz, beaten finalists by Munster in 2006 and Toulouse four years later, know that their over-exposure in Galway has pushed them to the brink of elimination.
Munster face another Titanic duel against Saracens on Sunday afternoon holding the psychological edge of a 15-9 home win during which Owen Farrell found out to his cost why English teams continue to be spooked by Thomond Park.
Without home comforts for the return, Munster will not need to be told that England's fly-half does not usually miss four shots at goal in one match, never mind on successive weeks.
How they stand halfway through the six-match pool competition:
1 - Harlequins 14 pts (14 tries)
2 - Clermont Auvergne 14 pts (1 tries)
3 - Ulster 14 pts (9 tries)
4 - Toulouse 13 pts (9 tries)
5 - Toulon 13 pts (7 tries)
6 - Saracens 10 pts (8 tries)
7 - Leicester 10 pts (9 tries)
8 - Munster 10 pts (6 tries)
9 - Leinster 9 pts (1 try)
10 - Montpellier 8 pts (7 tries)
11 - Castres Olympique 8 pts (4 tries)
12 - Racing Metro 8 pts (4 tries)
13 - Connacht 8 pts (3 tries)
Out:
Edinburgh, Benetton Treviso, Zebre, Glasgow Warriors, Cardiff Blues, Scarlets.
On their knees:
Sale Sharks, Biarritz Olympique, Exeter Chiefs, Ospreys, Northampton.
63x46.png){kind=logo}