The squad includes six players making a return having missed out from O'Sullivan's last squad.

In the backs, Ulster wing Tommy Bowe returns after missing out due to a hamstring injury and is joined by the uncapped Munster centre Barry Murphy. 

The other uncapped player in the backs is Leinster's Robert Kearney, whose good form over the last number of weeks has seen him included.

In the forwards, Munster hooker Jerry Flannery returns from his shoulder injury which saw him miss out last year and is joined in the squad by Munster second row Mick O'Driscoll. 

Leinster's Trevor Hogan is also named for the first time in an Ireland squad for an Six Nations Championship after winning two caps against Japan in 2005.

Stephen Ferris is the only player who was not considered due to his ongoing recovery from a hand injury, while Munster backrow Alan Quinlan was not considered due to suspension.

"The championship is a long and hard tournament that will always test your resources, so I felt that we needed to increase our squad to 35 to give us some extra cover," said O'Sullivan on his selection.

"We have a good injury profile at the moment and with the return of players from injury, such as Tommy Bowe and Jerry Flannery as well as the other additions to the squad, it will push up the competition levels.  While there are not many changes from November, the squad is always selected on form and this group reflects that."

"The Six Nations Championship is our bread and butter tournament and is the one in which we always want to do well.  We were pleased with how the November series went, but this tournament is a step up and we will have to raise our performances another level." 

"An away trip to the Millennium stadium to play Wales is one of the toughest openings you could get at this moment in time and all we will be focusing on is trying to get the right performance against an excellent Welsh team."

Ireland Squad:

Forwards: Neil Best (Ulster), Rory Best (Ulster), Simon Best (Ulster), Simon Easterby (Llanelli), Jerry Flannery (Munster), Keith Gleeson (Leinster), John Hayes (Munster), Jamie Heaslip (Leinster), Trevor Hogan (Munster), Marcus Horan (Munster), Denis Leamy (Munster), Donncha O'Callaghan (Munster), Paul O'Connell (Munster), Mick O'Driscoll (Munster), Malcolm O'Kelly (Leinster), Frankie Sheahan (Munster), David Wallace (Munster), Bryan Young (Ulster).

Backs: Isaac Boss (Ulster), Tommy Bowe (Munster), Girvan Dempsey (Leinster), Gordon D'Arcy (Leinster), Luke Fitzgerald (Leinster), Shane Horgan (Leinster), Denis Hickie (Leinster), Robert Kearney (Leinster), John Kelly (Munster), Barry Murphy (Munster), Geordan Murphy (Leicester), Brian O'Driscoll (Leinster), Ronan O'Gara (Munster), Eoin Reddan (Wasps), Peter Stringer (Munster), Andrew Trimble (Ulster), Paddy Wallace (Ulster).