Five years to the day since Joe Schmidt brought Andy Farrell on board as his defence coach, his successor recruited a similarly influential assistant coach to his own backroom staff.
In January 2016, much was made of the fact that Paul O'Connell's retirement had left a quiet dressing room and that the former rugby league star, whose Lions tour speeches had become YouTube hits, would add some motivational oomph to proceedings.
Like Farrell, O'Connell has a name for rousing pre-game oration and at times his input on that front will be needed. But what the head coach wants from the former Ireland captain is his game knowledge, his empathy and his renowned attention to detail as he comes on board for the remainder of the World Cup cycle.
Just over a month after Farrell became a member of Schmidt's ticket in January 2016, O'Connell confirmed that he'd be retiring because of the hamstring injury he suffered at the 2015 World Cup.
His announcement came through the IRFU media channels and, while he has remained close to the performance side of the union in the years since, they have not been able to find a home for him.
He worked with the youngsters at Munster for a while, had a stint as forwards coach with the Ireland Under-20s and spent a season with Stade Francais. Last spring, he was brought in by Farrell to get a taste of things in the build-up to Ireland's loss to England at Twickenham.
Performance director David Nucifora spoke about not wanting to "waste a resource like Paul O'Connell", but there was a growing sense in the game that the year in Paris soured his experience.
With his young family, the all-consuming nature of the role appeared to concern a man for whom obsession was a trademark characteristic during his playing days.
With a variety of ambassadorships and business interests and his role with the BBC keeping him in touch with the game, he was in danger of slipping out of it completely until yesterday's announcement. Television's loss is Ireland's gain.
O'Connell's remit within the Irish set-up will primarily focus around the lineout.
With Rory Best retired and Devin Toner out of the picture, the set-piece struggled in 2020 and, while O'Connell can't go out and call things himself, his input in preparing the set-piece will be invaluable to the inexperienced players tasked with running things.
The most experienced lock in the set-up, Iain Henderson, is in danger of missing the Six Nations and, if he does, they will proceed with James Ryan leading the lineout with either Rob Herring or Ronan Kelleher throwing in.
Although Herring made his debut alongside O'Connell, he remains inexperienced at this level while the Leinster young gun is still raw.
With Simon Easterby juggling the lineout and defence, the team's set-piece was not at the level it had been at times under Schmidt.
Easterby can now focus on implementing the defensive system, while his old team-mate can bring his remarkable knowledge to the lineout.
For Ryan, O'Connell's presence will be invaluable as he looks to take the next step as a leader. Named captain when Johnny Sexton was out injured during the autumn, the 24-year-old at times looked burdened by the responsibility.
Having a 108-times-capped former Ireland and Lions captain who played in the same position will be huge for Ryan, while O'Connell's presence will also be a boon for Sexton who is close to his old skipper and will respect his input.
For Farrell, whose coaching ticket looked a little thin, the move is a shrewd one, but for Nucifora, this is an investment in Irish rugby's future.