A big afternoon and evening of entertainment is planned as the spirit and traditions of Welsh rugby are celebrated at Parc y Scarlets.
With more than 204 internationals and 26 British and Irish Lions honours produced from the Llanelli and Scarlets stable over the years, this is another chance for supporters of West Wales rugby to celebrate a rich and colourful heritage.
Newly-appointed Scarlets President Phil Bennett will launch 5,000 Scarlets balloons from the centre of the pitch before kick-off, there will be a big choral performance accompanied by the Burry Port Brass Band and a host of community activities in the Scarlets' aptly named Canolfan Delme Thomas - the indoor supporters village.
And Scarlets supporters will be joined by some well-known special guests currently based in New Zealand on the big screen just before kick-off who are eager to send a message to everyone back in their regional home ahead of the game.
This week a host of former Scarlets greats and legends of the game have sent their best wishes to the Scarlets ahead of the landmark match as they signed a new commemorative memory wall, to be housed in the Supporters Village - marking the 5,000th game.
Ieuan Evans, one of the most famous and successful wingers to have ever donned a Scarlets shirt and captained Llanelli in 1996/97 said: "There was a responsibility with wearing that Scarlets shirt, the tradition of winning things, and I'll remember two great wins for Llanelli against Australia although I won't forgive Rupert Moon for the celebration he made us do after the try in 1993, but that was a special victory.
"Stradey had such a hold, such a history that were played out in those stands and those seats. The spiritual side of things is important for supporters and players alike, and the Scarlets have that - it's those intangible things, a key component in what defines you and to me sport should be about emotions. People care about teams, the club, the ground they come to watch their players at."
Ieuan who played a total of 231 games for Llanelli scoring 193 tries said he remembered his first game for the region back in 1984. He said: "It was mid-week against Gloucester, I was playing alongside Grav - it was a bit of a blur he didn't stop talking and telling me he'd look after me which he did, but even at the start you felt the responsibility and excitement of that shirt.
"Its good to see that spirit going full circle and now and the Scarlets have some young players doing so well in the World Cup. So much of the responsibility which we bore as players was to the type of rugby we played - the Scarlets way, the adventure it showed, the positive way to play the game and the excitement for supporters about the prospect of watching a Scarlets team play."
And Evans said it was good to see that style of play and approach to the game continuing down West and now having an impact on Wales' campaign in the World Cup.
He said: "The majority of the Scarlets players that have gone out to New Zealand are backs and their style will now have major bearing on the success of Wales, not just the Scarlets, in the near future. It's great to see the likes of George North, Rhys Priestland, Scott Williams and Jon Davies doing so well.
"These young guys are the ones who are driving this Wales side forward, with their energy and dynamism. That adds something, that can in turn energise the more senior players."
Scarlets Captain and Wales and Lions hooker, Matthew Rees said: "Being part of this club every player is well-aware of our great traditions especially the more senior players, we respect the people that have worn the jersey and what it means. It's part of what makes Scarlets rugby unique.
"We also have a lot to look forward to ahead of us as a region, as we can see the progression we are making as a group with so many young players coming from within our system - shown by the make-up of Wales' World Cup team with a number of young Scarlets involved.
"To reach 5,000 games is a huge achievement and one we should celebrate and I know the players will be feeling that when they take on some formidable opposition in Leinster. So the more that can come out and support us on this big occasion for us all as a region, the better."
Chief Executive of the Scarlets, Mark Davies said: "This landmark game is as much about our great heritage and recalling the amazing stories and memories that make up our 139 year history, as it is about the promise for the future and community spirit within this region.
"The same motivation, spirit and values run through this business today and it is important that we pay tribute to our great traditions as well look ahead to our future vision and philosophy to develop Welsh talent within our region."
The Scarlets will welcome 15 mascots who will walk with each of the starting 15 players for the big occasion from clubs associated with the club from across its region.
Llanelli's history dates back to 1872 when the town side played at People's Park. Its history is unrivalled in international rugby - with the Scarlets producing 204 internationals as well as 26 British and Irish Lions which includes Carwyn James and Gareth Jenkins as coaches.
BE PART OF HISTORY AND SUPPORT YOUR SCARLETS THIS SATURDAY AT PARC Y SCARLETS! The Supporters Village at Parc y Scarlets will be open from 4.30pm with a host of activities including the 5000th game memory wall which is open to all to sign with their best memories, Scarlets players or matches.