Real Madrid has signed Spanish midfielder Asier Illarramendi from Real Sociedad after paying a big buy-out clause, ending his long relationship with the fellow La Liga side.

In a press conference on Friday at Real Sociedad's stadium, the 23-year-old star said the decision to leave the club that groomed him was "very difficult" but that the opportunity was too big to pass up.

The Blancos reportedly signed the player for six seasons after paying a buy-out clause of 38 million euros ($49.4 million), taxes included, which makes the transfer the most lucrative deal in Real Sociedad's history.

The player returned Thursday to Real Sociedad's training facility in the northern town of Zubieta after helping lead Spain to the title in the Israeli-hosted 2013 UEFA European Under-21 tournament.

Illarramendi was applauded by several hundred fans when he took the field 30 minutes after most of his teammates.

One young autograph-seeker asked the player - a product of Real Sociedad's youth system - if he intended to stay with the team, but Illarramendi did not respond.

Illarramendi broke down in tears on a couple of occasions during Friday's press conference, saying that Real Sociedad had given him "everything" and adding that he had "arrived as a boy (but was) leaving as a man." EFE