Ireland coach Andy Farrell made nine changes Thursday to his starting side to face Japan in the Nations Championship this weekend, with Tadhg Beirne named to lead out the team as captain for the first time.
Only six players from their nail-biting 33-31 victory over the Wallabies in Sydney last week keep their place for the showdown in Newcastle on Saturday.
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They are backs Stuart McCloskey, Jamie Osborne and Jimmy O'Brien, along with forwards Tom O'Toole, James Ryan and Jack Conan -- with Farrell having an eye on a blockbuster clash with New Zealand at Eden Park on July 18.
Connacht back-row forward Sean Jansen will start for the first time at No.8, with provincial teammates Billy Bohan and Sam Illo also set for debuts off the bench.
Ulster flanker Bryn Ward was also included in the matchday squad for the first time.
"Really excited about this one for all sorts of reasons," said Farrell.
"Obviously, it's always a special occasion when you give one person a debut, never mind four.
"I'm looking forward to how they apply themselves to attacking the game first and foremost, because that's the roles they're able to add to the team.
"But also making sure that the rest of the team are there to support them for it to be a special day for them."
Having started on the wing last weekend, Osborne switches to fullback in a back three alongside O'Brien and Jacob Stockdale.
Robbie Henshaw comes into centre to partner McCloskey, with a new-look halves pairing in Craig Casey and Ciaran Frawley.
In the pack, the front row sees O'Toole, Ronan Kelleher and Thomas Clarkson combine, with the experienced Beirne partnering James Ryan in the second row.
Beirne has taken over the captaincy on-field before, but never started as skipper.
As for Japan, returning coach Eddie Jones has kept university student fly-half Ryunosuke Ito in their starting line-up.
Ito made his international debut in Japan's 27-10 win against Italy in Tokyo last week and the 21-year-old impressed enough to keep his place alongside half-back partner Naoto Saito.
"He's a young 10, he's going to have his ups and downs but we've got a team that's going to support him," said Jones.
"Those guys will help look after him and we just want him to be himself."
Taira Main replaces Kippei Ishida on the left wing in Japan's only change for Saturday's Test which will be played in Newcastle, Australia.
Jones returns after serving a four-match ban imposed by the Japan Rugby Football Union for abusing match officials on a tour of Australia earlier this year.
Ireland (15-1): Jamie Osborne; Jimmy O'Brien, Robbie Henshaw, Stuart McCloskey, Jacob Stockdale; Ciaran Frawley, Craig Casey; Sean Jansen, Nick Timoney, Jack Conan; James Ryan, Tadhg Beirne (capt); Tom Clarkson, Ronan Kelleher, Tom O'Toole
Replacements: Tom Stewart, Billy Bohan, Sam Illo, Cormac Izuchukwu, Bryn Ward, Nathan Doak, Harry Byrne, Bundee Aki
