Arsenal have completed the £45m signing of Thomas Partey from Atletico Madrid.
The Gunners triggered the Ghanaian midfielder's release clause earlier this afternoon and he has now completed his medical and agreed personal terms with the Premier League outfit.
Thomas has signed a five-year contract at the Emirates Stadium, keeping him in North London until 2025.
"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," technical director Edu told Arsenal's official website.
"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."
Manager 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."
Atletico confirmed earlier on Monday night that Thomas had terminated his contract with the club after his buyout clause had been met.
"La Liga informed Atletico de Madrid at 11.28pm on Monday that Arsenal representatives have paid Thomas Partey's release clause at the sports association's headquarters," read a statement from the Spanish outfit.
"The player has therefore unilaterally terminated his contract with our club, which ran until June 30, 2023."