Dan Biggar has given Wales' NatWest 6 Nations hopes a lift by returning from injury for Saturday's clash against Ireland in Dublin.
The Ospreys fly-half has recovered from a shoulder problem that ruled him out of Wales' opening two games against Scotland and England.
Biggar returns to the starting line-up instead of Rhys Patchell, while there are two other changes from the side beaten 12-6 by England at Twickenham 10 days ago.
Full-back Leigh Halfpenny has recovered from a foot infection and replaces Gareth Anscombe, while Saracens wing Liam Williams is in for Worcester's Josh Adams.
Biggar features for the first time since he was hurt during the Ospreys' European Champions Cup defeat against Clermont Auvergne last month.
Williams, meanwhile, suffered an abdominal injury during the autumn campaign and has not played for Wales since they beat Georgia in November.
Both Patchell and Adams drop out of the match-day 23, and Northampton wing George North remains on the bench with Gatland opting for a back-three of Halfpenny, Williams and Steff Evans.
Gatland has named an unchanged pack, including number eight Ross Moriarty, who missed Gloucester's Aviva Premiership game against Worcester last weekend after suffering a shoulder knock.
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
The game comes too soon for Lions No 8 Toby Faletau, who has resumed training after a knee injury.
Gatland, who takes charge of Wales for his 100th Test this week, said: "It is great to be able to bring so much experience back into the starting XV and into the back-line.
"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."
Victory for Wales at the Aviva Stadium would keep them in the Six Nations title mix ahead of home games against Italy and France next month.
But defeat in Dublin would potentially render the race for silverware a two-horse race between Ireland and reigning Six Nations champions England.
Wales: Leigh Halfpenny; Liam Williams, Scott Williams, Hadleigh Parkes, Steff Evans; Dan Biggar, Gareth Davies; Rob Evans, Ken Owens, Samson Lee; Cory Hill, Alun Wyn Jones (captain); Aaron Shingler, Josh Navidi, Ross Moriarty.
Replacements: Elliot Dee, Wyn Jones, Tomas Francis, Bradley Davies, Justin Tipuric, Aled Davies, Gareth Anscombe, George North.
Follow Ireland v Wales on Saturday (KO 2.15pm) via the live blog on RTÉ.ie/Sport and the News Now App, or listen live on RTÉ Radio 1, with commentary from Michael Corcoran and Donal Lenihan.