Eintracht Frankfurt midfielder Omar Mascarell has joined Schalke on a four-year deal with Real Madrid receiving €6m from the transfer.
The 25-year-old – who made nine La Liga appearances for Los Blancos in the 2012/13 campaign – joined the Bundesliga club in July 2016 and has impressed in Germany.
Real Madrid had an agreement with Frankfurt that they would trigger his €4m return clause and now they have sold him on, at a €2m profit, to their Bundesliga rivals.
Schalke will play in the Champions League next season and while the idea had been for Mascarell to play pre-season with Madrid, they have sanctioned his early exit.
Borussia Dortmund, Hoffenheim and Schalke have all previously been linked with a deal to the Tenerife-native, who has also had stints with Derby County and Sporting Gijon.
The European champions have retained the right of first refusal on any future move for the midfielder.