The Blues have already snapped up Italian midfielder Jorginho this summer, with Kovačić now joining him at Stamford Bridge in an attempt to find regular first-team football.
The Croatian playmaker has struggled to command a place in Real Madrid's since his arrival in the Spanish capital three years ago from Inter. His bit part role has left him frustrated despite Los Blancos' continued success in the Champions League, leading him to a seek for move in search of regular action.
Kovačić's wish has become Chelsea's command, with a statement on the Blues' official website confirming his capture for the forthcoming season:
"Mateo Kovacic has joined the Blues from Real Madrid on a season-long loan deal. The 24-year-old Croatian international arrives with experience having featured regularly in Serie A, La Liga, the Champions League and at international level. He played five games Croatia's run to the World Cup final this summer."
Kovačić's arrival at Stamford Bridge will provide new manager Maurizio Sarri with a timely boost ahead of the new Premier League season, as the Italian coach looking to imprint his attacking philosophy upon his new charges.
The 24-year-old will bring plenty of top level experience with him to England, having made over 150 league appearances for Inter and Real in his career thus far.
Upon his arrival at the club, the midfielder expressed his delight at signing for the Blues: "I am really happy and excited to be here at Chelsea. It is an amazing feeling. 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 team-mates will help me and I am looking forward to a great season."
He has played a part in each of Real's three Champions League winning campaigns, as well as capturing the La Liga title in 2016/17 and two Super Cup trophies. Despite his impressive trophy cabinet, many of those appearances have come from the substitutes bench - something that Kovačić will look to change during his season long spell in England.
He will compete for a place in central midfield with Cesc Fabregas and Ruben Loftus-Cheek among others, with Jorginho and N'Golo Kante likely guaranteed starting berths this season.