Manchester United have signed starlet Alvaro Fernandez Carreras on a free transfer from Spanish side, Real Madrid.

The 17-year-old has reportedly signed a four-year agreement with the Red Devils after the left-back became a free agent.

His deal at the Bernabeu expired on June 30 and he failed to agree an extension with Los Blancos.

He was part of the Juvenil C side in Madrid this campaign.

Carreras has impressed on his rise through the youth ranks since joining from Deportivo three years ago.

Carreras wrote on his Instagram page: “I have made the decision to leave this great club, I wanted to thank all my teammates, and the entire coaching staff at Real Madrid for making me a better person and footballer.

“It has been a real pleasure to wear this shirt, and represent this shield, it is time to say farewell and take another path in my football career, take a step forward towards my dream. Thank you Real Madrid!”