The former Marseille midfielder had been strongly linked with a Premier League move.
The 22-year old has earned rave reviews for his performances in the heart of the Marseille midfield and his comparisons to one Claude Makelele had led to considerable interest across Europe.
Inter were reportedly favourites for his signature but a late swoop from Porto has seen the Primeira Liga runner-ups secure his talents.
Earlier this month, Tottenham Hotspur were strongly linked, with The Mirror reporting a Benjamin Stambouli swap deal was on the cards, and just three days ago Southampton were said to be ‘confident of securing a deal’ for the midfielder, again by The Mirror.
All speculation can now be put to bed after Porto acted decisively in putting some of their incoming Jackson Martinez fee to good use.
The combative midfielder joins for around £14 million on a five-year deal with a release clause of £50 million included in the contract.
His departure follows the Marseille exits of Andre Ayew, Dmitri Payet and Andre-Pierre Gignac and hints at difficult times ahead at the Velodrome.