Brian O'Driscoll will make his 150th Leinster appearance and he partners Gordon D'Arcy in a back-line which includes six Ireland internationals.
Fergus McFadden, who kicked 18 points in the 38-3 win over Glasgow last Friday, moves to the right wing in a back-three which includes Luke Fitzgerald and Isa Nacewa.
Former Ulster scrum half Isaac Boss starts at half-back alongside Jonathan Sexton, who comes in for the benched Ian Madigan.
Cian Healy will have his 50th Magners League runout for Leinster, having been named in the front row alongside Richardt Strauss and Mike Ross.
Leo Cullen captains the side and starts in the second row alongside Nathan Hines with Shane Jennings, Sean O'Brien and Jamie Heaslip completing the pack.
Heinke van der Merwe has been named on the replacements bench alongside Ireland internationals Kevin McLaughlin, Eoin Reddan and Devin Toner.
Discussing Friday's interprovincial derby, Leinster's consultant scrum coach Greg Feek said: "Last week against Glasgow we let ourselves down a bit (in the scrum). I was a bit disappointed after the weekend.
"Good teams need to be at a level every week. Against Ulster this week, they're a difficult pack and we can't afford to have any more up-and-down periods.
"We're demanding from the boys and the boys themselves are demanding to get our stuff right, the little things right and the attitude right.
"This is a knockout game and we want to win it. Ulster are a team you have to respect. They have Rory Best up front, they will be missing BJ (Botha) but they have got good loose forwards and (Johann) Muller's there as well.
"He strengthens their set piece and they have got a good half-back obviously in (Ruan) Pienaar as well. We'll need to be on our game to beat them."
Ticket sales have passed the 14,000 mark for Friday's semi-final and are on sale now and will also be available at the gate on the night.
Prices start at €30 for adults and €10 for children while family tickets are also available for only €70 for a family of four.
Tickets are now on sale online here or you can also walk in and by them from any Ticketmaster outlet, Spar or the Leinster Rugby Store Donnybrook and Champion Sports in Grafton Street.
LEINSTER (v Ulster): Isa Nacewa; Fergus McFadden, Brian O'Driscoll, Gordon D'Arcy, Luke Fitzgerald; Jonathan Sexton, Isaac Boss; Cian Healy, Richardt Strauss, Mike Ross, Leo Cullen (capt), Nathan Hines, Sean O'Brien, Shane Jennings, Jamie Heaslip.
Replacements: Jason Harris-Wright, Heinke van der Merwe, Stan Wright, Devin Toner, Kevin McLaughlin, Eoin Reddan, Ian Madigan, David Kearney.