West Ham have confirmed the signing of Boavista defender Gonçalo Cardoso on a five-year deal.
The highly-rated 18-year-old defender has moved to the London Stadium for an undisclosed fee, having made his breakthrough at first team level last season.
The Hammers took to their official website to confirm the deal, with the teenager expressing his delight at moving to England.
He said: "I am very excited and it’s a dream come true. I always dreamt of coming to England and now I’m here at this big, historic club, so I’m very happy.
"I’m an aggressive player, a little bit different on the pitch than off it. I’m calm, and I like to have the ball and build the game from the back. I’m here to work and to help the team reach their goals."
Director of football Mario Husillos, who oversees much of the club's transfer policy, added: “We are very pleased to welcome Gonçalo to West Ham United. He is a young player at the very beginning of his career, having made the breakthrough to senior football with Boavista only last season.
“Our scouts in Portugal have watched his development very closely for some time now and we are very happy to have secured his transfer.
“He has made excellent progress at both club and international level, playing for Portugal in the European Under-19 Championship final this summer.
“He is of course a player for the future, with a lot of potential in front of him, but we feel he is ready to be with the first team squad from both a physical and technical point of view.
“He has a very good character and mentality, and speaks good English, which will help him to settle more quickly as a young player arriving in a new country.
“We look forward to seeing Gonçalo continue his development with us and wish him much success in the future at West Ham United.”
Cardoso made 15 appearances for Boavista last season, helping to keep eight clean sheets in the games he played. He is expected to join up with the club's Under-23s for now, though he has been awarded the number 20 shirt already.