Sunderland AFC can confirm that Martin O'Neill has been appointed as the club's new manager.
The 59-year-old has agreed a three-year deal on Wearside and will take charge of the Black Cats from Monday.
Vastly experienced, O'Neill has built a reputation as one of British football's most admired managers, steering Aston Villa to three successive sixth-place finishes in the Barclays Premier League between 2008 and 2010 after successful spells at the helm of Leicester City and Celtic - winning domestic honours and securing European qualification with both.
Speaking after officially joining the club, O'Neill said: "It's a very nice feeling to be back in football and to be the manager of Sunderland. It's a big moment for me.
"I'd heard about what a good club it was but coming here, seeing the stadium and training ground, I've been bowled over. It's absolutely fantastic.
"I hope I can help Sunderland to very successful period. That's what I've come for and that's my driving ambition."
After cutting his managerial teeth with Grantham Town and Shepshed Charterhouse, O'Neill rose to prominence in charge of Wycombe Wanderers between 1990 and 1995, taking the Chairboys from the Football Conference to the third tier of English football in successive seasons before a brief spell with Norwich City.
He swapped Carrow Road for Filbert Street in December 1995, steering Leicester City to promotion to the Premier League via the play-offs in his first season.
Winning two League Cups (1997 and 2000) and finishing runners-up in a third League Cup Final (1999) during his tenure in the East Midlands, he also guided the Foxes to four consecutive top ten finishes between 1997 and 2000.
O'Neill's success with Leicester attracted the advances of Scottish Premier League side Celtic and, in summer 2000, he moved north to Glasgow to guide a side which had finished 20 points behind champions Rangers in the preceding campaign to the domestic treble in his first season.
The Northern Irishman won three SPL titles, three Scottish Cups and a League Cup in his five years at Celtic Park, guiding the Bhoys to UEFA Champions League qualification on three occasions and the 2003 UEFA Cup Final. He also set a British record of 25 consecutive victories.
He left Parkhead in May 2005, returning to football - and the Barclays Premier League - a year later where he revitalised Aston Villa's fortunes to guide the club to 11th in his first campaign and sixth-place in the next three consecutive seasons. O'Neill led Villa to the League Cup Final in 2010, finishing as runners-up.
O'Neill is expected to be in the stands at Molineux for Sunday's clash with Wolves, however Eric Black takes charge of the team for the game.