Manchester United have completed the signing Uruguayan right-back Guillermo Varela from Atletico Penarol for an undisclosed fee.
Varela, 20, had a trial at Old Trafford last season and is David Moyes's first signing as Manchester United manager.
The defender has made one appearance for Penarol but has nine caps for Uruguay's Under-20 side.
"I'm very pleased to be a part of this club, one of the best in the world," he said after signing a five-year deal.
"As everyone in the world knows, this is a huge club that has won everything and I really hope that continues."
Varela is taking part in the Under-20 World Championships, which runs from 21 June to 13 July, in Turkey.
Last week, Penarol head coach Jorge Da Silva, who is reported to have since resigned, said he believed the youngster has earned the move.
Da Silva said: "This is what he deserves. It is a shame to see him go but you can't deny him the opportunity to join a club like this."
Rafael was United's regular right-back last season, with Phil Jones and Chris Smalling also featuring in the role.