The mouth-watering climax to this season's RBS 6 Nations sees the cream of Celtic talent on show, with 42 of the 44 players named by Wales and Ireland today plying their trade each week in an increasingly intense and exciting Magners League.
Both captains, Ryan Jones of Wales and Brian O'Driscoll of Ireland, have a wealth of Magners League experience behind them.
O'Driscoll leading his province Leinster to the title last season, taking over the mantle from Jones' region, the Ospreys.
The cross border rivalry will continue into April as both Wales and Ireland each have two representatives in the quarter-finals of the Heineken Cup.
Munster will host the Ospreys, the Cardiff Blues will welcome three-times winners Toulouse, while Leinster are set to travel to Harlequins.
The bulk of the players on the pitch on Saturday will also have a say in the outcome of those matches.
And with the forthcoming British and Irish Lions tour to South Africa now less than 11 weeks away, Celtic players are anticipated to feature strongly in the squad selection.
David Jordan, director of Celtic Rugby, said: "There is no doubt that the quality and competitiveness of the Magners League is now reaping its rewards in preparing the players of Ireland, Scotland and Wales for the increased intensity and pressure of European and international rugby.
"Good luck to all those involved in the games on Saturday."