Andy Farrell has been appointed as Ireland defence coach.
Farrell, who left his position as assistant England coach last month, will take up the role following this season's RBS 6 Nations Championship, the Irish Rugby Football Union announced.
The IRFU said Farrell's contract would commence ahead of the June tour to South Africa and run until the completion of World Cup 2019 in Japan.
Farrell and his fellow England assistants Graham Rowntree and Mike Catt departed Twickenham following Australian Eddie Jones' appointment as head coach.
The trio were part of an England coaching team headed by Stuart Lancaster, with Lancaster leaving the Rugby Football Union in November following a dismal 2015 World Cup campaign in which England failed to reach the quarter-finals following defeats against Wales and Australia.
In a statement released by the IRFU, Farrell said: "To have this opportunity to work with a very talented management and playing group really excites me.
"With a wealth of top-class experienced senior players and a fantastic crop of youngsters pushing hard, the future is very positive for Irish rugby, and I can't wait to get started."
Ireland head coach Joe Schmidt added: "It's great to have Andy coming into our coaching team.
"The quality of his delivery and breadth of his experience, as well as the positive impact he had when coaching a number of our senior players during the 2013 Lions tour, will add real value for us."
Farrell, 40, spent four years as an England assistant coach, in addition to being part of Warren Gatland's coaching support staff on the 2013 British and Irish Lions tour that was highlighted by a 2-1 Test series victory over Australia.
He won eight England caps as a player, including three appearances during the 2007 World Cup, after switching codes and joining Saracens.
Farrell had enjoyed an outstanding rugby league career, one that saw him make 370 appearances for Wigan, in addition to collecting England and Great Britain honours.