Antonio Conte has been appointed Chelsea's first-team head coach on a three-year contract.
Conte succeeds Jose Mourinho, who was sacked as manager in December, and will take up his role after managing Italy in this summer's European Championships, Chelsea announced.
The 46-year-old said on chelseafc.com: "I am happy we have made the announcement now so everything is clear and we can end the speculation.
"I will continue to focus on my job with the Italian national team and will reserve speaking about Chelsea again until after the Euros."
Conte has the unenviable task of rebuilding a side which won the Premier League title last season before imploding this term.
Mourinho's second spell came to an end on December 17 after a miserable start to the season and a "palpable discord" with his players, according to Chelsea technical director Michael Emenalo.
Guus Hiddink has restored stability in his second interim spell as boss - the Blues are 10th with seven games to go - but Chelsea face a rare season without a trophy and will be without Champions League football next term.
Conte guided Juventus to three successive Serie A titles before taking over the Azzurri and is used to success himself.
He becomes the fifth Italian boss of Chelsea - following Gianluca Vialli, Claudio Ranieri, Carlo Ancelotti and Roberto Di Matteo - and the eighth permanent boss appointed during Roman Abramovich's 13-year ownership. Mourinho was appointed twice, while there have also been caretaker spells for Hiddink, Rafael Benitez, Steve Holland and Ray Wilkins.
Conte added: "I am very excited about the prospect of working at Chelsea Football Club.
"I am proud to be the coach of the national team of my country and only a role as attractive as manager of Chelsea could follow that.
"I am looking forward to meeting everyone at the club and the day-to-day challenge of competing in the Premier League.
"Chelsea and English football are watched wherever you go, the fans are passionate and my ambition is to have more success to follow the victories I enjoyed in Italy."
Despite not taking up the job until after Euro 2016, Conte will now have the opportunity to shape Chelsea's strategy in the remainder of the season.
One of Conte's first tasks will be to decide the future of captain John Terry.
The 35-year-old defender in January announced he would be leaving Chelsea at the end of the season, but the club insisted a contract offer could be forthcoming.
Chelsea's players, some of whom reportedly want to leave given the absence of Champions League football next term, may also be appeased by the end of the uncertainty over the identity of their boss.
Chelsea director Marina Granovskaia said: "We are very pleased to have recruited one of the most highly regarded managers in world football and we are equally pleased to do so before the end of the current season. This aids our future planning.
"I would also like to take this opportunity to thank Guus Hiddink, who has done a great job since he joined us in December."
Chelsea chairman Bruce Buck added: "Antonio Conte has a record of consistent success in his career as a manager and as a player.
"We look forward to welcoming him to Stamford Bridge and are confident he will find all he needs to maintain that high standard of achievement."