Chelsea have signed Mateo Kovacic on a five-year deal from Real Madrid.
The midfielder initially moved to Stamford Bridge on loan last summer, helping the Blues to win the Europa League in May.
He has now completed a permanent move, with the Blues expected to appoint Frank Lampard as their new manager in the coming days.
Kovacic told the club's official website: "I really enjoyed my season on loan with Chelsea, I feel comfortable at the club and like London and the Premier League very much. I am very happy to be able to join permanently.
"We had a successful year, winning the Europa League and I hope I can make a big contribution in the coming seasons."
The 25-year-old – who had been at Madrid since 2015 – made 51 appearances in all competitions for Chelsea, who finished third in the Premier League, but did not score.
Kovacic moves in the opposite direction to Eden Hazard, who completed his big money move to the Bernabeu last month.
Chelsea are currently banned from registering new signings until the summer of 2020 after being found guilty of breaching rules when signing youth players.
But they have been able to complete this signing as it is seen as an extension to the deal agreed when Kovacic joined on loan last summer, with Chelsea merely exercising their 'option to buy' clause.
