Roy Keane has returned to Nottingham Forest as assistant manager to Martin O'Neill, the Championship club have confirmed.
The former midfielder joins the club less than two weeks after O'Neill was named the new manager, teaming up once again with the man he was second-in-command to at the Republic of Ireland national team.
Keane first joined Forest at the age of 18 after impressing famous manager Brian Clough. He went on to spend three seasons with the Reds and played over 150 matches before being snapped up by Manchester United, where he established himself as a Premier League legend in a 12-year spell.
O'Neill expressed a desire to bring Keane to the City Ground upon his own appointment, saying: "We have had some discussions and I would like him to join. There is a spot open for him. It may happen but he has a number of things to consider personally and professionally."
But Forest revealed on Monday that both parties had come to an agreement to bring in the 47-year-old to work alongside the former Celtic manager.
"Nottingham Forest are delighted to confirm that former Red Roy Keane has returned to the club as assistant manager," a statement on the club's website said, adding that he begins work with O'Neill's backroom staff "with immediate effect".
Keane won seven Premier League titles, four FA Cups and a Champions League crown during a successful period at Old Trafford before he left for a season at Celtic.
Despite his success as a player, Keane has built a reputation for being involved in clashes with several squad members as a coach.
However, O'Neill believes that passion and spark are what make him so effective as a member of his coaching team.
"He was a great asset to me as assistant manager at the Republic of Ireland," he said recently. "He is tough to handle, no doubt, but that's what makes him special. He was a special player and you don't win things at Manchester United by just sitting around."