Hook handed fly-half role
James Hook will make his second start at fly-half in this season's RBS 6 Nations Championship when Wales face Ireland on Saturday.
Hook, who wore the number 10 shirt and guided Wales to victory over Scotland at Murrayfield last month, replaces Stephen Jones.
Jones is on the bench, with fit-again Scarlets centre Jonathan Davies returning to midfield alongside Jamie Roberts after Hook deputised for him against Italy 10 days ago.
One other change from Rome sees a recall for Cardiff Blues wing Leigh Halfpenny, who is preferred to the unlucky Morgan Stoddart, a try-scorer against England and Italy.
Wales coach Warren Gatland has otherwise retained the team that triumphed at Stadio Flaminio, which means scrum-half Mike Phillips and number eight Ryan Jones will both win their 50th caps.
Despite Wales reporting a number of injury niggles on Monday, Gatland brought forward his team announcement by 48 hours.
He will choose two from three back-five forwards - Rob McCusker, Andy Powell and Jonathan Thomas - after fitness checks on Thursday, while there is a confirmed place among the substitutes for Sale scrum-half Dwayne Peel.
Gatland, who will break the Wales coaching record of 35 Tests in charge on Saturday, eclipsing Alan Davies' mark, said: "This is a crucial game for us as a win will keep us in the Championship mix and take us into that final round with everything still to play for. But it is also a big game for Ireland, who are in a similar position to us going into this match."
Wales team: L Byrne (Ospreys); L Halfpenny (Cardiff Blues), J Roberts (Cardiff Blues), J Davies (Scarlets), S Williams (Ospreys); J Hook (Ospreys), M Phillips (Ospreys); P James (Ospreys), M Rees (Scarlets, capt), C Mitchell (Ospreys), B Davies (Cardiff Blues), A-W Jones (Ospreys), D Lydiate (Newport Gwent Dragons), S Warburton (Cardiff Blues), R Jones (Ospreys).
Replacements: R Hibbard (Ospreys), J Yapp (Cardiff Blues), D Peel (Sale Sharks), S Jones (Scarlets), M Stoddart (Scarlets), plus two from R McCusker (Scarlets), A Powell (Wasps) and J Thomas (Ospreys).