The winger moved to Stamford Bridge from Lille in 2012 and he leaves after seven years with legendary status, winning six trophies, playing 352 matches and scoring 110 goals.
Hazard enjoyed a super final campaign at Chelsea - registering 21 goals, 17 assists and scoring twice in the 4-1 Europa League final win over Arsenal in Baku.
Now that Hazard is a Real player, the biggest domestic battles he will face are the Clasico clashes against Barcelona, who cruised to yet another La Liga title in 2018-19.
Their talisman is Lionel Messi, and even though Hazard has long dreamed of joining Madrid, he's suggested no one comes close to the Argentine's level on multiple occasions.
- Hazard's emotional message to Chelsea fans
- Real's potential 2019-20 XI after Hazard joins
- Messi's 2018-19 stats v 2018 Ballon d'Or top 3
Hazard v Messi: The dribbling kings
Hazard has signed a five-year contract at Los Blancos, managed by his idol Zinedine Zidane, and the transfer fee could exceed a whopping £150 million.
The Belgium captain will now be going head-to-head with Messi on a weekly basis in all things playmaking: goalscoring, assisting, chances created and dribbling.
Hazard's goals tally may not be at the level of Messi (who scored 51 times this season), but the pair, along with Neymar, are considered to be the best pure dribblers in world football.
What Hazard has said about Messi over the years
During some form of live stream for Chelsea TV, Hazard outright called five-time Ballon d'Or winner Leo Messi the best player in the world without any hesitation.
In addition to that, the 28-year-old was once asked to compare himself to Messi in a Belgium press conference before an international game, but he said that isn't possible.
"I can't be compared to (Lionel) Messi," Hazard, who was directly involved in more Premier League goals than anyone else this term, responded.
"Yes, there are some similarities, we're both small and fast, but he scores important goals in every game. I can't be compared to the incomparable."
So, Hazard, who transformed from a young talent to a world-class superstar at Chelsea, seems to have no doubts that the Barca captain is the world's best footballer.
Do YOU agree with Hazard? Do YOU think Messi is the world's best? Be sure to have YOUR say in the comments box below!