Ireland head coach Declan Kidney has named Rory Best and Marcus Horan in his 44-man squad for the RBS 6 Nations.
Ulster hooker Best has not played this season having undergone surgery on a neck injury last summer, but has recently returned to contact training having made good progress in his recovery.
Munster prop Horan returns having missed out on the autumn internationals after undergoing a routine medical procedure for a minor heart ailment.
The loosehead has not played for his province since the Heineken Cup win over Benetton Treviso in October but played 80 minutes for Shannon in their AIB All-Ireland league clash with Dolphin on Saturday.
There are nine uncapped players in the squad with Ulster forwards Dan Tuohy and Declan Fitzpatrick among the new faces.
Lock forward Tuohy has been in commanding form for the Ravenhill side, particularly impressing in the Heineken Cup wins over Stade Francais and Edinburgh. Fitzpatrick is a more surprising selection given that he has only started two games for the province this season.
The other uncapped men are Leinster's Fergus McFadden, Kevin McLaughlin, Devin Toner and John Fogarty , Leicester wing Johne Murphy, Connacht prop Brett Wilkinson and powerful Ulster number eight Chris Henry.
Kidney will select the Ireland A squad to face England Saxons in Bath on January 31 from his 44-man panel, with players being brought in from outside the squad for that fixture. The A side will then face Scotland A at Ravenhill on February 5.
The head coach, who was unable to select wing Luke Fitzgerald and number eight Denis Leamy due to injury, admits his selection was made with one eye on developing his squad ahead of the 2011 World Cup.
He said: "When naming the squad, we had three main considerations, with the most important being the opening game against Italy, followed by the A games and further down the line with the Rugby World Cup.
"Building a squad has always been a priority for us and the work done during the first half of the season means there is a little more experience accumulated in the squad then we had a couple of months ago.
"While there were new players who gained vital experience during the Guinness Series, the goal is to keep that experience ticking over with all the players who need international-level game time.
"By having the A games early, it allows us to get people on the pitch so they can keep their own performance levels up as we progress through to the later stages of the championship."
Key figures from last season's first Grand Slam success in 61 years, such as talismanic captain Brian O'Driscoll and second-row Paul O'Connell, will look to try to guide Kidney's side to the first back-to-back Slams since France achieved the feat in 1997 and 1998.
Fly-halves Ronan O'Gara and Jonathan Sexton are set to provide Kidney with his most troubling selection headache after the precociously-talented Sexton took his chance to impress in the autumn victories over Fiji and South Africa.
Competition will also be tight at scrum-half, with Peter Stringer, Isaac Boss, Tomas O'Leary and Eoin Reddan all earning places in the squad.
Leinster loosehead prop Cian Healy will look to try to nail down his position in the side after filling Horan's shoes admirably during the autumn.
Veteran tighthead John Hayes, set to win his 100th cap during the tournament, is also included, although Kidney may be tempted to give the likes of Ulster's Tom Court and Leinster's Mike Ross a run bearing in mind Munster forward Hayes will be 37 when the World Cup comes around.
Although Kidney knows his squad have a shot at creating history, the former schoolteacher insists they are fully focused on their opening clash with Italy at Croke Park on February 6.
"The provinces have all been in good form, making selection even more competitive, but we will need that for the big challenges that are ahead for the group over the next couple of weeks." he said.
"The focus is very much on our game against Italy in a fortnight's time and we are preparing for that first challenge".