Once again it's Ireland who lead the way in terms of GUINNESS PRO12 contributors, as all 23 players in the match day squad play for one of the four provinces.
As they take on Scotland, it's second place Leinster who provide the most players, 11 in all between the starting lineup and the bench.
Five players from Leinster will start the game, but it's Munster who have the most starters in all with six, including Tommy O'Donnell, the only change to the team that put nine tries past Italy last weekend.
Meanwhile Ulster have three starters, including captain Rory Best, and GUINNESS PRO12 leaders Connacht have Robbie Henshaw in the starting lineup, the Irishman proving one of the star performers in the RBS 6 Nations so far.
It will be a last chance for the Irish players to join forces before a huge table-topping clash in the Guinness PRO12 next weekend when Connacht host Leinster.
Meanwhile the Ulster players in the Irish side will be looking to get one over on their Scottish rivals a week before they travel to take on Glasgow Warriors in a key match in the league.
Ireland will face an array of Scottish GUINNESS PRO12 talent, a total of 18 of the 23 Scots coming from the championship.
Reigning GUINNESS PRO12 champions Glasgow lead the way with six starters, including in-form full-back Stuart Hogg who was so impressive in victory over France last week, and there are five more Warriors on the bench.
Edinburgh, and their dominant front row of Al Dickinson, Ross Ford and WP Nel, provide four starters in all, and two more on the bench, while Wales-based John Barclay is also in the team from the Scarlets.
In the opening game of the day it is the might of Wales who will be looking to secure second place in the Championship, against an Italian team hoping to sign off with a first success.
There are ten Welshmen starting who ply their trade in the GUINNESS PRO12, with five Ospreys including new Welsh captain Dan Lydiate.
He takes over from the injured Sam Warburton, and is joined by fellow Osprey Justin Tipuric in the back row which is completed by Taulupe Faletau of the Dragons, fresh from his try against England.
As with Leinster and Connacht, there will be plenty of edge to this one, with the Ospreys set to host the Scarlets in a big Welsh derby next week.
Finally, Italy have ten GUINNESS PRO12 starters, with a full bench from the league and it's Zebre who lead the way. They have six starters and a further four on the bench, including debutant Jacopo Sarto.
With five new GUINNESS PRO12 faces brought in this weekend, that brings us up to 109 players in all from the championship in this year's RBS 6 Nations.
Ireland have provided 34 players, with Italy and Scotland next up with 27 and 26 respectively. Finally Wales, with their settled squad have had 22 GUINNESS PRO12 players feature in the 2016 edition.
As we are now at the business end of the GUINNESS PRO12, the clubs will be relishing the return of such a wide ranging collection of talent.
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