Zinedine Zidane says he has "recharged his batteries" and wants to bring the glory days back to Real Madrid.
Real confirmed the reappointment of the Frenchman on Monday evening after sacking Santiago Solari following a disappointing campaign so far.
Zidane, who left Real last summer after two and half years in charge, has signed a contract at the Bernabeu until June 2022 and says he is looking forward to managing the Spanish giants for a second time.
"I have been living here in Madrid, doing my things, but I have recharged my batteries. I'm ready to coach this great club again," he told a press conference.
"It has been difficult from outside looking in. I am looking forward to working with the players again, to competing again.
"I'm just happy to come back. I want to work and to provide what's needed to get the club to where it should be."
Zidane was first appointed Real Madrid boss in January 2016 after a spell in charge of the B team, and he became the first coach to win the Champions League in three straight seasons. He won nine major trophies during his time at the club, including the La Liga title in 2016-17.
However, Zidane returns to Real at a difficult time. Back-to-back defeats to Barcelona in the Copa del Rey and La Liga saw their domestic season fall apart, before a surprise 4-1 second-leg defeat at home to Ajax saw them knocked out of the Champions League at the last-16 stage.
Zidane says there is work to be done to turn the club's fortunes around.
"Things will have to change. I am here because the president called me," he added.
"I love this club very much and here I am. We have 11 games left this season and we want to do as well as we can.
"When you have won a lot, it's normal that you have a dip. I watched from outside, but it's as if I was still here. I'm not happy with what has happened. We have to look at what is missing. First we need to look at what we need now and after that, what we need for the coming seasons."
Zidane will take his first training session on Tuesday before returning to the Real dugout against Celta Vigo at the Bernabeu on Saturday.