Johnny Sexton has been appointed Ireland captain for the Six Nations, while new head coach Andy Farrell has named five uncapped players in his 35-man squad.
Fly-half Sexton takes on the role following the retirement of vastly-experienced former skipper Rory Best.
Leinster trio Ronan Kelleher, Caelan Doris and Max Deegan are among the potential Test debutants selected for the tournament, along with Ulster pair Billy Burns and Tom O'Toole.
Sexton, who has won 94 caps, has not played since suffering a knee injury playing for Leinster in early December but, according to his club side, is making "good progress" in his recovery.
The 34-year-old's only previous experience of captaining his country came in October during the World Cup pool stage win over Russia.
"We have appointed Johnny as captain for the Six Nations Championship, you can see what it means to him and the enthusiasm he will bring to the role," coach Farrell told the Irish Rugby Football Union website.
"He has been developing as a leader for a number of years with Ireland, Leinster and the Lions and he will be a positive voice for the group."
Ireland begin the tournament on Saturday, February 1 at home to Scotland.
Sexton said: "First of all it's a massive honour to be asked to do it and I obviously got a taste for it during the World Cup for that one game and I've done it in patches with Ireland in-game when either Rory or Pete have gone off in previous games.
"It's something that I enjoy but ultimately it's a huge honour, the biggest honour of my career to be asked to do it and I'm really looking forward to it and looking forward to the challenges that are coming up and hopefully we can have a successful Six Nations."
— Irish Rugby (@IrishRugby) January 15, 2020
Ireland Six Nations squad
Forwards: Max Deegan (Leinster)*, Caelan Doris (Leinster)*, Ultan Dillane (Connacht), Tadhg Furlong (Leinster), Cian Healy (Leinster), Dave Heffernan (Connacht), Iain Henderson (Ulster), Rob Herring (Ulster), Ronan Kelleher (Leinster)*, Dave Kilcoyne (Munster), Jack McGrath (Ulster), Jack O’Donoghue (Munster), Peter O’Mahony (Munster), Tom O’Toole (Ulster)*, Andrew Porter (Leinster), James Ryan (Leinster), CJ Stander (Munster), Devin Toner (Leinster), Josh van der Flier (Leinster)
Backs: Will Addison (Ulster), Bundee Aki (Connacht), Billy Burns (Ulster)*, Ross Byrne (Leinster), Andrew Conway (Munster), John Cooney (Ulster), Keith Earls (Munster), Chris Farrell (Munster), Robbie Henshaw (Leinster), Dave Kearney (Leinster), Jordan Larmour (Leinster), Luke McGrath (Leinster), Conor Murray (Munster), Garry Ringrose (Leinster), Jonathan Sexton (CAPTAIN, Leinster), Jacob Stockdale (Ulster)
* Denotes uncapped player