At Croke Park on Saturday, RG Snyman will make his Croke Park debut for Leinster and also play against his former team.
An elite group of players have played for both Munster and Leinster, and here's a selection of players who've made the journey from Munster to Leinster, or vice versa.
A selection of players to have lined out for both Leinster and Munster
Andrew Conway
Starting off with the man whose retirement saddened many within Irish rugby this week. Andrew Conway made the move to Thomond Park in the summer of 2013, just after starting both the Challenge Cup final and the Pro12 final victories for Leinster on home soil.
Despite those successes, it is arguably for his time at Munster - and his iconic try against Toulon in 2018 - that Conway will be best remembered, with the Blackrock College man breaking into the Ireland team during his time at Thomond Park.
Conway retires with 150 appearances for Munster, 42 for Leinster, and 30 Ireland caps to his name.
Paul Wallace
Back during the early 90s, when inter-provincial rugby clashes attracted similar crowds to Railway Cup matches, Paul Wallace was a key cog in the Munster scrum.
After the 1994-95 season, in which Munster unseated Ulster as inter-provincial champions after ten straight victories, Wallace chose to declare for Leinster for work purposes.
He played in Leinster's first ever game in the Heineken Cup in Milan where his bacon was saved by second row Brian Rigney who stopped an opposing forward from taking his head off.
In the great exodus of 1996, he left for Saracens but was to return in due course, playing for Leinster in the early 2000s.
Wallace has told us that he was the common denominator in victory in every Munster-Leinster game in which he played. He never lost a Munster-Leinster game on either side.
I was lucky enough never to lose for one side against the other from all levels. But yeah, putting an Irish jersey on to play against England was like playing for Munster against Leinster. There was always that competitiveness. When you came up to play for Leinster, you knew what you were going to get on the other side.
You always get a particularly nice welcome from the Munster pack if you've actually left. Except for my brothers, they did look after me once or twice when on the other side.... There's a couple of draws there I think at u-20s, one for Munster against Leinster and we drew one senior game in Musgrave Park in around 2002, but other than that, yeah, clean sheet.
Eoin Reddan
A product of the Limerick club rugby scene, Reddan was given his first chance by Connacht in 2001. He moved back home to Munster in 2003 only to serve two years as understudy to Peter Stringer. He played just under 30 games in two seasons, almost all of them coming in the Celtic League.
One of those players whose career was rejuvenated rather than hindered by a move to the Premiership.
Tadhg Beirne
A pivotal cog in not only Munster's current team, but with Ireland as well, Beirne has been one of the country's most consistent performers in recent years.
He arrived at Munster via Llanelli, with the lock spending two seasons with Scarlets - which included a victory over Munster in the 2017 Pro12 final. However, he came through the academy at Leinster, having attended school at Clongowes Wood College in Kildare.
Beirne made just four first team appearances for Leinster, spending most of his time in the province with the 'A' team - with whom he won the 2013 British and Irish Cup.
One of the biggest success stories on this list when it comes to moving south.
Mike Ross
Like the two above him in this list, Mike Ross didn't transfer directly from province to province, spending some time developing his game in the hothouse of the Aviva Premiership in between.
Ross began his professional career at Munster but could not dislodge John Hayes from the tighthead prop role. Ross spent three years at Harlequins, playing in the infamous bloodgate game in 2009. In the off-season he would move to the other side of the fence, joining Leinster.
READ HERE: Expiring Contracts For Kleyn And Snyman Leave Munster With A Decision To Make
Joey Carbery
Still on the books with Munster, Joey Carbery moved from Leinster in the summer of 2018 with both a Champions Cup and a Pro14 medal in his back pocket.
He has struggled to stay fit for much of his time in Limerick, but has nonetheless added a URC medal to his collection since joining Munster.
Tony Ward
Indelibly associated in the folk memory with Munster, Ward declared for Leinster in 1982. He made no secret of the fact that business commitments had forced his hand.
At the time he owned sport shops in Dublin city centre and Dun Laoghaire and was playing club rugby with Greystones.
It is a decision I have taken with regret but one forced on me by circumstances.
Ward stuck with Leinster until the end of his playing career, moving to centre from 1986 onwards to accommodate Paul Dean at outhalf.
Liam Toland
Toland commenced his career with Munster in the mid-1990s but found it difficult to break into the back row which contained internationals Eddie Halvey and David Corkery.
He suffered a career threatening injury in 1997 during an AIL game for Old Crescent against Shannon. After a spell out of the game, Mike Ruddock took him to Leinster in 1999.
John Fogarty
Another who began at Munster before ending up at Leinster, Fogarty represented three of the four provinces and spent the bulk of his career in Connacht. He was at Munster during the agonising early years of the noughties when the side excelled but fell short against Europe's best in the latter stages.
He spent the last two seasons of his career at Leinster before being advised to retire following repeated concussions. He won a Heineken Cup with Leinster in 2009.
Trevor Hogan
Born in Tipperary, Hogan is a rare example among his generation in swapping directly from Munster to Leinster. After spending the early portion of his career at Munster, he moved to Leinster in 2006. He retired through a knee injury in 2011.
Niall Ronan
Now more readily associated with Munster, Ronan began his career with Leinster during the mid-noughties. Like many others, injury forced his relatively early retirement from the game.
Felix Jones
Jones made one appearance for Leinster in the Sportsground in their victorious 2007-08 Magners League campaign. He played numerous times for the Leinster 'A' team before transferring to Munster ahead of the 2009/10 season.
Has gone on to achieve extended notoriety outside of Ireland as part of Rassie Erasmus' South Africa coaching team.
This article was originally written by Conor Neville in 2015.