The Portuguese coach, 50, travelled to London on Monday to complete the formalities of a second stint in charge at Stamford Bridge after his exit from Real Madrid was confirmed, penning a four-year deal.
Mourinho was headhunted by the Blues after guiding Porto to Champions League glory in 2004, and would lead Chelsea to successive Premier League titles in 2005 and 2006, before leaving after his relationship with owner Roman Abramovich broke down.
Success has followed elsewhere - a treble with Inter Milan and the Spanish title in his second season at Madrid - but Mourinho has never attempted to play down his love affair with the Chelsea faithful.
"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 on Chelsea TV today.
"I never hide that in my career in football I had two great passions, Inter and Chelsea, and Chelsea is more than important for me.
"It was very hard to play against Chelsea, I did it twice which was not so bad.
"Now I promise exactly the same things I promised in 2004, but with the difference we have (now), which is I am one of you."
Chelsea chief executive Ron Gourlay insists moving to bring back the self-proclaimed 'Special One' was the only option as he looked to take the club on following the reign of interim manager Rafael Benitez.
The Spaniard replaced Champions League-winning coach Roberto Di Matteo in November 2012 and, after some initial difficulties, guided the Blues to a third-place finish as well as winning the Europa League.
"I am delighted to welcome Jose back to Chelsea. His continued success, drive and ambition made him the outstanding candidate," Gourlay said on the club's official website, www.chelseafc.com.
"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."
Mourinho will be officially unveiled at a press conference at Stamford Bridge on June 10, and is set to bring assistant coaches Rui Faria, Silvino Louro and Jose Morais to Stamford Bridge where they will work alongside current first-team staff Steve Holland, Christophe Lollichon and Chris Jones.
The Portuguese manager, who also claimed the FA Cup and the League Cup twice during his last spell at Stamford Bridge, will inherit a squad which has appeared to come through the challenges of Andre Villas-Boas ill-fated "project" to deliver elite European football once again, as well as another piece of silverware to the trophy cabinet.
Nevertheless, Mourinho - who won a second Champions League trophy with Inter Milan in 2010 - is expected to bring in some reinforcements ahead of the new season, with £15million-rated Roma midfielder Daniele De Rossi a reported target.
One player who is certain to be an integral part of the Blues side again next season is Frank Lampard.
The 34-year-old England midfielder broke the club's long-standing goal-scoring record this season and agreed a 12-month contract extension.
Lampard told BBC Sport: "He's a great manager, I've said it a million times to the point of boring people, but I'm very fortunate to have worked under him before.
"He took my game on a million miles, and my personality in terms of football on a million miles. A lot of the reasons I moved on in the game is because of him.
"He's taken that (a winning mentality) everywhere he's gone with him. He creates a spirit in his squads that you can see from the outside is very, very strong. He's a top class manager, we all know that."
The new Blues manager will look to shape his squad during their tour of Asia, which sees matches in Bangkok, Kuala Lumpur and Jakarta from July 17.