It should have actually been the final but Leinster and Munster will fight it out on Friday for a place in this years Guinness PRO14 final.
They will battle it out at the Aviva Stadium and the defending champions will go in as favorites, but Munster have a score to settle.
Leinster will be trying to get a third title in a row but they first have to get pass Munster on Friday. Munster last won the championship in 2011.
Leinster got a narrow win over Munster two weeks ago beating their rivals 27-25 at the same venue.
Munster have named a strong side for the semi final which include Springbok World Cup winner, Damien de Allende in the midfield partnering with Chris Farrell. Chris Cloete will start on the bench for Munster.
At home Leinster will be hard to beat as always but if their is one side that can upset the champions then it is Munster.
Leinster Leo Cullen has made a few changes from the team that beat Ulster last week.
This sees the return of captain Johnny Sexton at flyhalf.
Jordan Larmour comes in at fullback with Hugo Keenan and James Lowe on the wings. Robbie Henshaw and Garry Ringrose are in the midfield, with Luke McGrath at nine.
This is going to be a cracker and it will be broadcast live on SuperSport on Friday
Leinster: 15 Jordan Larmour, 14 Hugo Keenan, 13 Garry Ringrose, 12 Robbie Henshaw, 11 James Lowe, 10 Johnny Sexton (c), 9 Luke McGrath, 8 Jack Conan, 7 Will Connors, 6 Caelan Doris, 5 Scott Fardy. 4 Devin Toner, 3 Andrew Porter, 2 Ronan Kelleher, 1 Cian Healy.
Replacements: 16 Sean Cronin, 17 Ed Byrne, 18 Michael Bent, 19 Ryan Baird, 20 Josh van der Flier, 21 Jamison Gibson-Park, 22 Ross Byrne, 23 Rory O’Loughlin.
Munster: Shane Daly; Andrew Conway, Chris Farrell, Damian de Allende, Keith Earls; JJ Hanrahan, Conor Murray; Jeremy Loughman, Niall Scannell, Stephen Archer; Tadhg Beirne, Billy Holland; Peter O’Mahony (C), Jack O’Donoghue, CJ Stander.
Replacements: Kevin O’Byrne, James Cronin, John Ryan, Fineen Wycherley, Chris Cloete, Craig Casey, Rory Scannell, Mike Haley..