Porto have signed Brazilian midfielder Casemiro on a season-long loan deal from Real Madrid.
The 22-year-old, who moved to Madrid from Sao Paulo in January 2013, has made 27 appearances in all competitions for Real but could join Porto permanently next summer.
A statement published on Porto's official website read: "Porto have secured Brazilian midfielder Casemiro from Real Madrid for one season. The Dragons have an option to purchase him at the end of that period.''
The 27-time Portuguese champions finished in a disappointing third place in 2013-14 and new head coach Julen Lopetegui -- the former Real Madrid goalkeeper -- has been working hard to rebuild the first-team squad ahead of the new Primeira Liga campaign.
Attacking midfielders Adrian and Oliver Torres have arrived from Atletico Madrid, right-back Daniel Opare has signed after leaving Standard Liege, and around 19 million euros have been spent on bringing Yacine Brahimi, Bruno Martins Indi and Cristian Tello to the Estadio do Dragao.