The 22-year-old scored 23 goals last season, including 17 in Ligue 1, despite Marseille struggling and finishing 13th ‒ just nine points clear of the relegation zone.
His performances earned him a place in Belgium’s Euro 2016 squad and he scored within two minutes of his introduction as a substitute against Hungary in the last 16.
Speaking to Chelsea’s official website, Batshuayi said:
‘I am delighted to sign for one of the biggest clubs in Europe and embark on the next chapter in my career.
‘I hope I can help Chelsea win many trophies during my time at Stamford Bridge.
‘Eden Hazard and Thibaut Courtois have told me many good things about the club, and with Antonio Conte coming in it’s an exciting time to become a Chelsea player.
‘This is a fantastic opportunity for myself and my family, I am looking forward to playing in the Premier League next season.’
The centre-forward has already confirmed that he will wear the No.23 shirt for Chelsea in the coming season, but what can Chelsea fans expect from the Belgium striker?
First things first: goals. In his relatively short senior career, he has scored wherever he has been. He managed 23 goals for Standard Liege in the 2013/14 season to help the club finish as runners-up in the Belgian league, before moving to Marseille where he found the net 33 times in 78 appearances.
At 5ft 11in he is not as physically imposing as Drogba, but he is still powerful, strong and determined like the Chelsea legend.
While comparisons with Drogba are of course premature, the Ivorian was four years older when he made the same move from Marseille to west London for a similar fee – they will likely be inescapable.
The Blues haven’t had much luck signing strikers of late. Batshuayi suggests a change in tack from the Falcao/Loic Remy model. He is a young, exciting striker with great potential and, although expensive, looks set to help Chelsea compete at the right end of the Premier League next season under Conte.