Martin O'Neill has been named as the new manager of Aston Villa.
O'Neill will bring in coaches John Robertson and Steve Walford
O'Neill replaces David O'Leary, who was sacked by the Midlands club last month, on a 12-month rolling contract
The 54-year-old had been away from football for over a year after quitting his position at Celtic in May 2005 to look after his ill wife Geraldine.
The former Northern Ireland midfielder has previously managed Wycombe, Leicester and Celtic - where he won the Scottish Premier League three times.
John Robertson and Steve Walford also join Villa as assistant manager and coach.
O'Neill takes the reins at Villa Park in time for the club's pre-season tour of Germany and Holland, which begins on Saturday.
He was met by over 1,000 fans when he arrived at Villa Park and said he was "overwhelmed" by his reception.
"This is a fantastic challenge," O'Neill said. "I am willing and ready to go.
There are some funds available to strengthen the squad and I am going to use them
New Villa manager Martin O'Neill
"I am well aware of the history of this football club. Trying to restore it to its days of former glory seems a long way away - but why not try?
"It is nearly 25 years since they won the European Cup but that is the dream."
O'Neill has just over two weeks to prepare for his side's first game of the new Premiership season - against Arsenal at the Emirates Stadium on 19 August.
"There are some funds available to strengthen the squad and I am going to use them," O'Neill added.
"I will have to look quickly at how the players are shaping up. I have seen quite a few players from a distance but you don't get to know them properly until you work with them yourself.
"There's not a great deal of time but that should not matter too much - life's not ideal like that."
Villa chairman Doug Ellis was delighted to have secured O'Neill as the club's new manager.
Ellis said: "To me, Martin's passion and ability to motivate players is unsurpassed.
"We had three meetings at my home and I've not spoken to anyone else.
"We had a dozen applicants but Martin was my choice at the start and here he is today."
It is six years since O'Neill last managed in the Premiership with Leicester but he is confident he will settle in quickly.
"I have a reasonable idea of what the Premiership is about," O'Neill stated.
"The game has probably changed a little bit but I'm not blind to it and I'm hoping to adjust and adapt relatively quickly."
"It's absolutely fantastic to be back and with a club such as this.
"I have to prove myself to the fans but I'm ready for the job and want to do well. If Aston Villa are going to have a bit of success in the coming years, I'd like to be a part of that."
O'Neill, who spent the summer as a pundit for BBC Sport at the World Cup, joins a club in a state of uncertainty.
There are four consortia - led by American billionaire Randy Lerner, lifelong fan Michael Neville, deputy judge Nicholas Padfield QC and Sven-Goran Eriksson's agent Athole Still - all vying to buy out current chairman Doug Ellis.
All reportedly approved the appointment of O'Neill and his backroom team of Robertson and Walford.
O'Neill began his managerial career at Shepshed Charterhouse before moving on to Grantham then Wycombe and finally Leicester, who he guided to four successive top-10 Premiership finishes and three League Cup finals, of which he won two.
That got him the job at Celtic, where he won three SPL titles in five years and also took the club to a Uefa Cup final.