Manchester United have completed the signing of full back Diogo Dalot from Porto on a five-year deal.
The Portugal Under 21 international has joined the club for £17.4 million and has the option to stay an extra year in his contract.
United wanted a right back to compete with Antonio Valencia, who is 33 and needs constant treatment on a knee injury.
The 19-year-old can also play left back.
He broke into Porto’s first team in February in that position and played in his club’s 0-0 Champions League draw at Liverpool.
He helped Portugal win the 2016 UEFA European Under 17 Championship, scoring twice in five games in Azerbaijan including once in the final against Spain.
On signing the teenager, United manager Jose Mourinho told the club’s official website: “Diogo is an extremely talented young defender with all the qualities to quickly become a great player for this club.