Arsenal have signed Ghanaian international Thomas Partey from Atletico Madrid after paying his 50m euros (£45.3m) release clause.
The deal was completed just minutes before transfer deadline Monday.
The 27-year-old midfielder made 35 league appearances and scored three goals for Diego Simeone’s side as they finished third in La Liga last season.
He has made 29 international appearances for Ghana’s Black Stars and is part of the squad for the upcoming friendly against Mali in Turkey.
Technical director Edu, said: “Thomas has all the right attributes to be a top player for Arsenal. He is a leader on and off the pitch and he is exactly the kind of player and person we want at the club. We already feel like we know Thomas very well based on the work we have done analysing his performances closely in recent times.
“With his all-round game and positive aggressive style, he will be a brilliant addition to our squad. We’ve made a strong start to the season and we want to continue to build on this with Thomas now part of our club.”
Mikel Arteta added: “We have been watching Thomas for a while, so we’re now delighted to add such a high quality player to our squad. He is a dynamic midfielder with great energy. He brings a lot of experience from a top club that has competed at the highest level in La Liga and the Champions League for several years.
“We’re very impressed with his attitude and his approach to the game. He’s an intelligent footballer and we’re looking forward to him integrating into our system and contributing to the progress we’re building at the moment at the club.”
Partey will wear the No 18 shirt and will join up with his new team-mates next week after he returns from international duty with Ghana.
He played 188 times for Atletico after joining the club in 2011 winning both the Europa League and Super Cup in 2018, and a Champions League runner-up medal in 2016.
Uruguay midfielder Lucas Torreira, 24, has moved in the opposite direction and joined the La Liga side on loan.