London - Everton manager Ronald Koeman signed Senegal midfielder Idrissa Gueye from Aston Villa for £7.1 million on Tuesday.
Koeman triggered Gueye's buyout clause last week and the 26-year-old has agreed a four-year contract with the Premier League club.
Gueye is Koeman's second signing since the Dutchman arrived from Southampton to replace the sacked Roberto Martinez in June.
His only previous deal was a swoop for Fulham goalkeeper Maarten Stekelenburg.
"Idrissa will provide quality in our squad in the midfield and we want to increase the quality in the team," Koeman told Everton's website.
"He was one of the players last season with the best record in interceptions and pressing in the midfield. We need this kind of quality and I'm happy to have him joining our club."
Gueye was second only to Leicester's Premier League-winning midfielder N'Golo Kante, who has since joined Chelsea, in terms of the number of combined interceptions and tackles made across Europe's top five leagues.
He moved to Villa from French club Lille last year and made 38 appearances in all competitions as Villa were relegated from the Premier League.
"Everton is a big team with big players and great fans. The manager told me he is very happy to have me here and that we will have time to talk about football after," Gueye said.
"I have played a season with Aston Villa which was a hard season but I think my style is good for the Premier League. You have to fight every game."