The Italian spent seven years as a player at Chelsea, scoring 80 goals in 312 appearances
Gianfranco Zola is back at Chelsea as assistant manager to Maurizio Sarri.
The Blues legend returns to Stamford Bridge 15 years after making the last of his 312 appearances for the club.
Zola, who scored 80 goals for Chelsea between 1996 and 2003, won the UEFA Cup Winners’ Cup and Super Cup, two FA Cups and the League Cup.
The 52-year-old has had management experience in England with West Ham, Watford and Birmingham.
He told Chelsea’s official website on Wednesday evening: “For me it is an amazing thing.
“I am very willing to work hard because it is going to be a difficult challenge but I am pleased to be here, and to work hard with Maurizio to be successful.
“It would be great to be successful with Maurizio and for the club and I will give my best, as I did in the past as a player, so I will give my best in my new position.
“I am very much looking forward to the challenge in general. I would love us to start well and we are all very excited to start this new adventure.”
The news came on the same day that former Napoli boss Sarri had his unveiling at Stamford Bridge, having replaced Antonio Conte on Saturday.
Sarri’s first task will be convincing Eden Hazard and Thibaut Courtois to commit to Chelsea and forget about joining Real Madrid.
Belgium internationals Hazard and Courtois, who are recovering after helping their country finish third at the World Cup, have been heavily linked with Real.
Goalkeeper Courtois has just a year remaining on his Chelsea contract, while forward Hazard has an additional 12 months.
Chelsea’s failure to qualify for the Champions League will not aid Sarri’s cause but he is hopeful his coaching methods can convince the pair to stay.
“The players you are referring to are very high level players and I would like to keep them in my squad,” the Italian said at his unveiling on Wednesday.
“A telephone call without looking them in the eyes would not give me any certainty.
“I would like to meet these players face to face, talk to them and understand what the best thing to do would be for everyone.
“Before that I would also like a player to come on the pitch for four or five days together with me, to have a clear idea of what the situation is.
“Hazard is a very high-level player. He’s one of the top two or three European players.”