There are four changes to the side that beat the USA. Up front Cian Healy returns to the starting line-up at loosehead prop, having recovered from an eye injury.
He is joined in the pack by fellow Rugby World Cup debutant Sean O'Brien,who comes in to the back row alongside Stephen Ferris and Jamie Heaslip.
Eoin Reddan will start at scrum half, partnering his provincial colleagueJonathan Sexton, and Rob Kearney is set for his first start of the tournament at full-back.
Commenting on the selection, head coach Declan Kidney said: "The players coming back will bring freshness to the team. If you play the same team week in, week out, it becomes difficult for everybody.
"I didn't think Sean, Rob or Cian were as fit as they needed to be to play against the USA last week so they got another week under their belts.
"They're raring to go and that brings its own impetus into the team. Rob could have played last week but some guys have the capacity to come in and play well. Rob's shown that in the past and against Scotland last month.
"For him to be more confident that his leg isn't in any way an issue, I felt he should have another week off.
"You don't want a fella having what the medics call a chronic injury which is ongoing from week to week. We have a small bit of that already in that Stephen (Ferris) doesn't train every day. You don't want that right through the team."
The unfortunate news of Jerry Flannery's tournament-ending calf injury means that World Cup newcomer Sean Cronin is standing by for an appearance off the bench. Damien Varley has flown out as Flannery's replacement in the squad.
Meanwhile, Australia head coach Robbie Deans has selected his starting line-up and replacements for Saturday's encounter with Ireland. James O'Connor returns on the right wing as the only change in personnel.
With Digby Ioane sidelined by a thumb injury, O'Connor has been recalled to the Wallabies' back-line. The Western Force youngster will also assume the place-kicking role, taking over from out-half Quade Cooper.With the 21-year-old back in the side, there is a positional switch for fellow winger Adam Ashley-Cooper, who moves from the right to the left hand side of the backs division.
Drew Mitchell, the second top try scorer at the 2007 Rugby World Cup, has also been added to the replacements bench. He sat out the Tri Nations after sustaining an ankle injury during the Super 15 campaign.
Deans commented: "Drew has worked hard within the group, he has the background with us and is ready for this opportunity.
"While it is disappointing for Digby that he is going to be on the sidelines for a while, we are confident he will be available to us again before too long. His timelines will depend on how his rehabilitation goes, but the operation on Tuesday night went well."
Notably, Queensland's Anthony Fainga'a will become the seventh different centre to line up opposite Brian O'Driscoll in the 11 Tests that the Ireland captain has played against Australia since 1999.
In a late change to the Australian starting line-up, a back complaint has sidelined David Pocock for this game. His Western Force team-mate Ben McCalman comes on to make his World Cup debut, with Wycliff Palu added to the bench.
AUSTRALIA: Kurtley Beale (NSW Waratahs); James O'Connor (Western Force), Anthony Fainga'a (Queensland Reds), Pat McCabe (Brumbies), Adam Ashley-Cooper (Brumbies); Quade Cooper (Queensland Reds), Will Genia (Queensland Reds); Sekope Kepu (NSW Waratahs), Stephen Moore (Brumbies), Ben Alexander (Brumbies), Dan Vickerman (NSW Waratahs), James Horwill (Queensland Reds) (capt), Rocky Elsom (Brumbies), Ben McCalman (Western Force), Radike Samo (Queensland Reds).
Replacements: Tatafu Polota Nau (NSW Waratahs), James Slipper (Queensland Reds), Rob Simmons (Queensland Reds), Wycliff Palu (NSW Waratahs), Scott Higginbotham (Queensland Reds), Luke Burgess (NSW Waratahs), Drew Mitchell (NSW Waratahs).
IRELAND: Rob Kearney (UCD/Leinster); Tommy Bowe (Ospreys), Brian O'Driscoll (UCD/Leinster) (capt), Gordon D'Arcy (Lansdowne/Leinster), Keith Earls (Young Munster/Munster); Jonathan Sexton (St. Mary's College/Leinster), Eoin Reddan (Lansdowne/Leinster); Cian Healy (Clontarf/Leinster), Rory Best (Banbridge/Ulster), Mike Ross (Clontarf/Leinster), Donncha O'Callaghan (Cork Constitution/Munster), Paul O'Connell (Young Munster/Munster), Stephen Ferris (Dungannon/Ulster), Sean O'Brien (Clontarf/Leinster), Jamie Heaslip (Naas/Leinster).
Replacements: Sean Cronin (Leinster), Tom Court (Malone/Ulster), Donnacha Ryan (Shannon/Munster), Denis Leamy (Cork Constitution/Munster), Conor Murray (Garryowen/Munster), Ronan O'Gara (Cork Constitution/Munster), Andrew Trimble (Ballymena/Ulster).
Referee: Bryce Lawrence (New Zealand)
Assistant Referees: Dave Pearson, Stuart Terheege (both England)
Television Match Official: Graham Hughes (England)
