Brahim Diaz has completed a £15.5m move from Manchester City to Real Madrid, in a deal that could rise to £22m with add-ons.
Real Madrid confirmed the signing on Monday, several hours after Diaz had completed a medical, with the 19-year-old signing a six-and-a-half-year deal.
"I have arrived at a club that I dreamed of playing for as a child," an emotional Diaz said. "I could not have received a better Christmas present than wearing the Real Madrid jersey.
"When I decided that it was time to leave Manchester City, I only put three options on the table.
"The first, to play for Real Madrid; the second, to play for Real Madrid; the third, to play for Real Madrid.
"I never wanted to go anywhere else, it is impossible to go to a better club. I promise to give 100 per cent from the first day and to pay back the faith you have put in me."
Diaz's words of commitment to his new club were greeted with applause in the press room.
A clause in the deal means that Manchester City will receive 15 per cent of any future transfer fee, however, that will rise to 40 per cent if the buying club is Manchester United.
Diaz had rejected offers of a new contract from City and was set to become a free agent in the summer.