Gatland goes Biggar at pivot
Biggar, who missed the opening two matches of the Championships due to a shoulder injury, will make his 61st appearance for his country.
The flyhalf will line up alongside Gareth Davies at half-back.
TEAM NEWS 🏴 Wales welcome back @lionsofficial trio Dan Biggar, Leigh Halfpenny and Liam Williams for #IREvWAL. Croeso nol i Lewod Halfpenny, Williams a Biggar i wynebu Iwerddon dydd Sadwrn. pic.twitter.com/MDgRyrrmGM
— Welsh Rugby Union 🏉 (@WelshRugbyUnion) February 20, 2018
British and Irish Lions stars Liam Williams and Leigh Halfpenny have also been included in the starting XV.
Halfpenny has recovered from a foot infection and slots in at fullback, while Williams is on the wing.
The pair are joined by Steff Evans in the back-three with Hadleigh Parkes and Scott Williams continuing their partnership in the midfield.
Wales have named an unchanged pack for the trip to Dublin. The all-Scarlets front row of Rob Evans, Ken Owens and Samson Lee feature for a third consecutive game. Cory Hill partners captain Alun Wyn Jones in the second-row with Aaron Shingler, Josh Navidi and Ross Moriarty comprising the back-row.
"It is great to be able to bring so much experience back into the starting XV and into the backline," said head coach Warren Gatland, who will take charge of Wales for the 100th time.
"It is the first week we have had everyone in the ‘green’ in terms of availability which is a nice luxury to have and a positive ahead of what is a very important test match against a very good Ireland side.
"We have been pleased with the depth we have developed in the back-three and pleased with how those players have gone but having the experience of Dan, Liam and Leigh coming back in is hugely important.
"We have been pleased with how the forward pack has been going and how they have worked as a unit but as always there is pressure for them to perform too."
Elliot Dee, Wyn Jones and Tomas Francis are named as the front-row replacements with Bradley Davies and Justin Tipuric completing the forward contingent. Aled Davies, Gareth Anscombe and George North provide the back-line cover.
Wales: 15 Leigh Halfpenny, 14 Liam Williams, 13 Scott Williams, 12 Hadleigh Parkes, 11 Steff Evans , 10 Dan Biggar, 9 Gareth Davies, 8 Ross Moriarty, 7 Josh Navidi, 6 Aaron Shingler, 5 Alun Wyn Jones (captain), 4 Cory Hill, 3 Samson Lee, 2 Ken Owens, 1 Rob Evans
Replacements: 16 Elliot Dee, 17 Wyn Jones, 18 Tomas Francis, 19 Bradley Davies, 20 Justin Tipuric, 21 Aled Davies, 22 Gareth Anscombe, 23 George North
Date: Saturday, February 24
Venue: Aviva Stadium, Dublin
Kick-off: 14.15 (14.15 GMT)
Assistant referees: tbc
— Welsh Rugby Union 🏉 (@WelshRugbyUnion) February 19, 2018