The 24-year-old, who helped his country Croatia to the 2018 FIFA World Cup final where they faced off against France in a disappointing defeat, will now be plying his trade in the Premier League with the Blues 2018/19 campaign.
“I am really happy and excited to be here. It is an amazing feeling,” Kovacic speaking to Chelsea’s website.
“I will try to do my best for this club. It is a new league for me, the beginning is always tough but I am sure the coach and my new teammates will help me and I am looking forward to a great season.”
Chelsea director of football Marina Granovskaia also added: “He is a perfect fit for us this season, his style is well suited to how Maurizio [Sarri] wants to play and we are sure he will prove to be a valuable asset for the club.”
Since joining from Inter Milan, in his three years spent with Real Madrid Kovacic has helped the Spanish club to securing the Champions League three times in a row.
And also holding a record of being the second-youngest player to score in the Champions League against Lyon at the age of 17.