(CNN) -- Jose Mourinho has completed his widely-expected return to Chelsea after the English Premier League club ended weeks of speculation by confirming Monday that the former Real Madrid coach has agreed a four-year contract.
"I am delighted to welcome Jose back to Chelsea. His continued success, drive and ambition made him the outstanding candidate," Chelsea chief executive Ron Gourlay said in a statement.
"It is our aim to keep the club moving forward to achieve greater success in the future, and Jose is our number one choice as we believe he is the right manager to do just that.
"He was and remains a hugely popular figure at the club and everyone here looks forward to working with him again."
In his first interview since taking charge, the Portuguese told Chelsea TV that he was offering fans the same qualities that he did when he first took charge of the club nine years ago -- namely, a pledge to deliver quality work, love and passion to bring success to the Blues.
"It is exactly the same message but now I can say I am one of you -- and that makes a little bit of a difference," he said.
"In football, I had in my career two great passions: Inter and Chelsea. Chelsea is more important for me.
"It was very, very hard to play against Chelsea - I did it only twice, which was not so bad -- so now I promise exactly the same things that I promised in 2004, with the difference that I am one of you."
After leaving Chelsea in 2007, it was not until 2010 that Mourinho returned to Stamford Bridge as a visiting coach, winning a Champions League quarterfinal 1-0 in March 2010 to seal a 3-1 aggregate win for an Inter Milan side who would go on to lift that year's trophy.
Chelsea said the 50-year-old would bring his three coaching staff -- Rui Faria, Silvino Louro and Jose Morais -- who will work alongside the current first-team coaches Steve Holland, Christophe Lollichon and Chris Jones.
Mourinho first joined Chelsea on June 2, 2004 and dubbed himself "the Special One" after having led Porto to the European title the previous season.
He was unable to take Chelsea to the Champions League final, but guided the club to two successive EPL titles -- its first English championship successes since 1955.
After falling out with Chelsea's Russian owner Roman Abramovich in 2007, Mourinho joined Inter Milan the following season and won two successive Italian Serie A titles and the Champions League in 2010.
He was then courted by Real with the goal of ending the club's long wait for a record-extending 10th European title, but despite winning La Liga in his second season Madrid fell three times at the semifinal stage of the Champions League and his relationship with key Spanish players such as captain Iker Casillas deteriorated.
As in Italy, he had a prickly time with the local press -- who took every opportunity to publish stories about dressing-room unrest at the Santiago Bernabeu.
Real announced last month that he would be leaving, despite having signed a contract extension until 2016.
Mourinho's final game in charge of was Saturday's 4-2 win over Osasuna, which left the Spanish club in second place in La Liga -- 15 points behind Barcelona.
He did not talk to reporters after the match, though he did an interview with Spanish television in which he denied omitting goalkeeper Casillas and defender Pepe -- with whom he has had public disputes -- and top scorer Cristiano Ronaldo for any other reason than they were not fit enough to play.
"I wish everyone associated with Real Madrid much happiness in the future," he said in a statement on Friday.
"I appreciate the support of lots of fans and respect the criticism of others. Once again, a lot of happiness to everyone and, above all, good health. Hala Madrid!"
His return to Chelsea was one of the worst-kept secrets in world football -- the English Premier League jumped the gun by announcing his reappointment Sunday before a deal has been done.
The EPL's website published a story, dated Monday, with the headline "Jose Mourinho makes Chelsea return."
Its subheader read: "Portuguese coach back at Stamford Bridge after signing a XX-year contract."
The story was taken down, and the EPL issued a statement apologizing to Chelsea -- which was searching for a new manager following the departure of interim coach Rafael Benitez.
"It was a publishing error. We took it down as soon as we were notified of it, and we've spoken to and apologized to Chelsea," the EPL said.
Benitez led Chelsea to third place in the EPL, guaranteeing a place in the Champions League next season after taking over from the sacked Roberto Di Matteo in November.
The Spaniard also took Chelsea to success in the Europa League, with the club having dropped to the second-tier competition after becoming the first Champions League winner to fail at the group stage the following season.