Ireland hooker Rob Herring says the new faces in Andy Farrell's squad "have fitted in really well" ahead of Saturday's Six Nations encounter with Italy in Dublin.
Highly-rated Leinster duo Will Connors and Hugo Keenan will make their debuts from the start at the Avia Stadium
New additions Ed Byrne and Jamison Gibson-Park are named on the bench.
"He is an absolute machine in defence and his work rate is incredible," Herring said about flanker Connors.
"Defence is all about energy, body language and making other guys around you feel better. He beings that in spades.
"He is a good craic off the pitch and a great guy to have around the squad."
Everyone 'ready to go'
With Ireland's last Six Nations match coming in March before the Covid-19 pandemic halted the tournament, Herring says the goal is still the same for Andy Farrell's men.
Ireland sit fourth in the table after three matches, with wins over Scotland and Wales followed by a disappointing defeat to England in February, however they can still win the title if they win their last two matches and other results go their way.
"It has been a while since we played but we have two games to go and win a championship. The stage is still the same for us," said the Ulster hooker.
"We're always trying to refine the way we play. We've only had three games together under the new coaching staff, and we thought we were getting better and adapting.
"There are a lot of things going around at the moment and we know there is an opportunity for us to go out and put in good performances and something for people to be proud of.
"A championship at the end of it would be great for all the people who support us and the people we represent.
"It's a bit of a cliché, but we have Italy this week so we have to put in a good performance to win that game and come away with five points, which would put us in with a shot come the end of the tournament."