Atletico Madrid have signed midfielder Geoffrey Kondogbia from Valencia on a four-year deal, the club announced on Tuesday.
Kondogbia, 27 has been brought in to replace Thomas Partey since Arsenal paid his buyout clause on deadline day.
Atletico can bring in Kondogbia outside the transfer window because La Liga rules grant a club 30 days to find a replacement when a player's buyout clause has been paid.
He will compete for a place in Atletico's midfield with captain Koke, Saul Niguez, Hector Herrera and Lucas Torreira, who joined on loan from Arsenal this summer.
ESPN reported on Saturday that the deal was on the verge of completion, and Kondogbia travelled to Madrid on Sunday to undergo a medical.
The midfielder first shone in La Liga at Sevilla in the 2012-13 season, before moving to Monaco and Inter, and joining Valencia in 2017.
His departure is acrimonious, after Kondogbia accused Valencia and president Anil Murthy of reneging on an agreement to allow him to follow other key players such as Dani Parejo, Rodrigo Moreno and Ferran Torres in leaving Mestalla this summer.
"Having destroyed an ambitious project, you had to mislead your coach and finally me. Thank you, Anil Murthy," he posted on Instagram last month.
Valencia announced the player's departure with a curt, one-line statement, tweeting: "So long, Geoffrey Kondogbia."