Chelsea have confirmed the appointment of Andre Villas-Boas as their new manager on a three-year deal.
The former Porto boss, 33, will start work at Stamford Bridge immediately, the English Premier League club said on Wednesday.
It comes a day after the London club paid 15 million euros to release him from his contract with the Portuguese champions and his appointment comes a month after Carlo Ancelotti was sacked.
"Andre was the outstanding candidate for the job. He is one of the most talented young managers in football today and has already achieved much in a relatively short space of time," a statement on the club's website read.
"His ambition, drive and determination matches that of Chelsea and we are confident Andre's leadership of the team will result in greater successes in major domestic and European competitions."
"Andre will bring his coaching experience back to a club he is already very familiar with, having previously worked here for three years."
"He has always been highly regarded at Chelsea and everyone here looks forward to welcoming him back and working with him."
Villas-Boas led Porto through an undefeated league campaign and Europa League glory last season.
The Portuguese manager spent time working under Jose Mourinho at Chelsea and Inter Milan as head of opposition scouting - as well as a stint as assistant coach at Porto prior to that.
He moved to lead Portugal's Academica from a relegation battle to mid-table respectability before re-joining Porto a year ago.