Former Ireland captain Paul O'Connell has returned to the international set-up as forwards coach.
The appointment of the legendary lock sees Simon Easterby move to the position of defence coach.
O'Connell won 108 caps for his country in an international career that spanned 13 years and included three British and Irish Lions tours.
He retired in 2015 after an injury ruled him out of his side's World Cup quarter-final.
The ex-Munster forward has held coaching positions with the province's academy, Ireland Under-20s and Top 14 side Stade Francais since retiring.
He joins Andy Farrell's set-up exactly a month before Ireland kick off their 2021 Six Nations campaign against Wales in Cardiff.
"It's an exciting young group of players to be involved with," said O'Connell.
"There are talented forwards coming through across the four provinces that will no doubt be pushing for international selection in the coming months and years."
In his first year at the helm, Farrell experienced a mixed bag of results with the schedule heavily disrupted by the Covid-19 pandemic.
A clean sweep of home wins went some way to offsetting comprehensive away defeats by England and France.
Farrell worked with O'Connell on the 2013 Lions Tour of Australia, in which the visitors claimed their first Test series win in 16 years.
"Paul brings a wealth of rugby knowledge with him and as forwards coach he will have responsibility for the forwards including the line-out working alongside John [Fogarty]," Farrell said.
"He will also be another strong voice and leader within the group."