The Vigo-born 18-year-old, who is a member of the Spain Under-19 side, took his medical with Juve on Monday before penning his contract which ties him to the Serie A giants until June 30, 2012.

"I'm happy to have the chance to join a prestigious club such as Juventus," said Yago.

"I'm excited about the idea of being able to train with huge stars and I can't wait to begin.

"I hope I can make myself useful and show my skills. I wish to thank (Juve coach) Claudio Ranieri for the praise he bestowed on me and I'm committed to honouring his expectations."

Juve sporting director Alessio Secco added: "Yago is a very promising youth; we'd been following him for some time. He will need to get stronger and he'll be playing with the Youth Team.

"This signing confirms Juventus' regard for younger players," Secco told Juventus Channel.