Jose Mourinho said it was an "easy decision" for him to return to Chelsea for a second spell in charge.
It was announced on Monday that the 50-year-old had signed a four-year deal to manage the club he had previously helped to two Premier League titles.
"It was an easy decision," ex-Real Madrid boss Mourinho told Chelsea TV.
"I asked the boss 'do you want me back?' and the boss asked 'do you want to come back?' - after a couple of minutes the decision was made."
He added: "I'm very happy. I had to prepare myself to not be too emotional on my arrival at the club, but obviously I'm very happy."
The Portuguese manager, who also helped the Blues to two League Cup wins and one FA Cup triumph, takes over from interim boss Rafael Benitez following a three-year period in charge at Real Madrid.
He said that he would be looking to "improve the team" but not by spending millions in the transfer window.
"By that, I mean work with the team. My work has to improve the players and the team," added Mourinho.
"If I don't do that I won't be happy with myself. If after that we can further improve the team by buying couple of players, then fantastic - but I have to improve the team with my work."
Mourinho, who helped Real to the Spanish league title in 2012 and has won two European Cups with Porto and Inter Milan, said if it was up to him he would like to begin training with the squad straight away.
"I don't need a holiday," he added.
"I'm sorry that we aren't beginning training tomorrow. I say to the players during the season when they are tired that victories make miracles.
"When you win, win, win, you are never tired. In my case, it's about moving to a place I love. Happiness is stronger than tiredness."
Mourinho initially left Chelsea by mutual consent on 20 September 2007 after the club had made an indifferent start to the season which had seen them occupy fifth in the table.
There were also reports that his relationship with Russian owner Roman Abramovich had become strained.
"I think it was a difficult moment because you know I love it here and I have a big connection with the club - it wasn't easy for the club either," he said of that period.
"But if you analyse it, in a cool way, and leave your emotions aside, I think it was fantastic. I got what I aimed for in my career, while Chelsea also won more important trophies.
"We are now back together which is a great moment for both. We are ready to marry again and be happy and successful again."