Porto defender Diogo Dalot has completed a move to Manchester United after signing a five-year contract, the club has announced.
The 19-year-old, who reportedly had a £17.4million release clause in his contract, emerged from Porto's academy to make his Primeira Liga debut last season.
He has represented Portugal at U21 level but is yet to win a senior international cap.
United manager Jose Mourinho told manutd.com: "Diogo is an extremely talented young defender with all the qualities to quickly become a great player for this club.
"He has all the attributes that a full-back needs: physicality, tactical intelligence and technical quality, combined with a Porto Academy mentality which prepares players for the maturity they need at the professional level.
"In his age group, he is the best full-back in Europe and we all believe he has a bright future ahead of him at Manchester United."
👋 A big #MUFC welcome to @DalotDiogo!#BemvindoDalot 🇵🇹 pic.twitter.com/kYPAfmdapk
— Manchester United (@ManUtd) June 6, 2018
Dalot said he simply could not turn down the chance to join United and work under compatriot Mourinho.
He said: "Joining Manchester United is an unbelievable opportunity for me. I have grown up in Porto's Academy and I am so thankful for everything they have done for me.
"But the chance of coming to the biggest club in the world is something I just couldn't turn down.
"I'm excited about working with Jose Mourinho and learning everything I can from such a successful coach. I am looking forward to playing alongside the fantastic players in the squad."
Meanwhile United remain hopeful of retaining the services of Marouane Fellaini despite the player's apparent desire to leave the club.
It's understood Fellaini is now all but certain to end his five-year stint at Old Trafford and join a rival club when his contract expires at the end of the month.
But it is believed United are still keen to get the Belgium midfielder tied down to a new deal, with an offer remaining on the table to keep him.
Fellaini started just two Premier League games since the turn of the year and has been linked with a move away for some time.
Mourinho has expressed his desire to retain the services of the former Everton man, who moved from Goodison Park in 2013.
Speaking after Fellaini came off the bench to score a last-gasp winner against Arsenal in April, Mourinho said: "The position is that we are almost there but in football almost is not enough.
"I want to see the white paper with the United crest and Ed Woodward's signature and Marouane's signature."
An unnamed top-six Premier League side is understood to have shown firm interest in signing the 30-year-old on a free transfer, with Fellaini now seemingly swayed by the offer of more regular football.
