Ulster hooker Tom Stewart will start his first Test match after being named in the Ireland team to take on Samoa in Bayonne on Saturday (7.45pm).
The 22-year-old replaces the injured Dan Sheehan in the front row as he hopes to cement a place in Andy Farrell's 33-man World Cup squad, which will be announced on Monday.
Stewart, the URC's top try-scorer last season with 16, made his debut off the bench in the win over Italy at the start of the month.
Leinster’s Sheehan injured his foot in last weekend’s 29-10 win over England. An update on the in-form 24-year-old's injury is expected later this afternoon.
Stewart’s fellow Ulster team-mate Rob Herring is on the bench, with Rónan Kelleher still recovering from a hamstring injury.
Farrell said last week that Kelleher, Jack Conan (foot) and Dave Kilcoyne (hamstring) should be fit for selection for the tournament, which begins for Ireland on 9 September against Romania.
Elsewhere, Stuart McCloskey starts at inside centre as one of 12 changes to the team that extended Ireland’s winning streak to 12 games on Saturday.
Jimmy O’Brien is named at full-back with man of the match against England Mack Hansen on the right wing and 100-cap Keith Earls on the left at Stade Jean Dauger.
Robbie Henshaw starts outside McCloskey with Conor Murray partnering Munster team-mate Jack Crowley in the half-backs for the reigning Six Nation champions.
Stewart will have Cian Healy and Finlay Bealham with him in the front row, while Iain Henderson captains the side in the second row with Tadhg Beirne for company.
The back row is an all-Leinster line with Ryan Baird at 6, Josh van der Flier at 7 and Caelan Doris at the back of the scrum.
Herring, Jeremy Loughman and Tom O’Toole provide the front row cover on the bench, with James Ryan and Peter O’Mahony in reserve to cover the second and back rows, respectively.
Craig Casey, Ross Byrne and Garry Ringrose are the backs replacements.
Ireland are currently ranked number one in the world, with opponents Samoa ranked 12th.
Captained by Leinster prop Michael Ala’alatoa, Samoa have already beaten Japan and Tonga, Ireland’s second opponents in Pool B, this summer.
Ireland: Jimmy O'Brien; Mack Hansen, Robbie Henshaw, Stuart McCloskey, Keith Earls; Jack Crowley, Conor Murray; Cian Healy, Tom Stewart, Finlay Bealham; Iain Henderson (capt), Tadhg Beirne; Ryan Baird, Josh van der Flier, Caelan Doris.
Replacements: Rob Herring, Jeremy Loughman, Tom O'Toole, James Ryan, Peter O'Mahony, Craig Casey, Ross Byrne, Garry Ringrose.
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Watch live coverage of Ireland v Samoa on Saturday 26 August on RTÉ2 and RTÉ Player, listen to live commentary on RTÉ Radio 1 Extra or follow a live blog on RTÉ.ie and the RTÉ News app.
