Chelsea signed striker Romelu Lukaku for a second time on Thursday as the Belgian returned to the Premier League club from Inter Milan, seven years on from his departure.
A Chelsea statement did not mention the agreed transfer fee, but media reports say the deal is worth a club record 97.5 million pounds ($134.7 million).
Lukaku has penned a five-year deal at Stamford Bridge.
The Belgium international leaves Inter after two successful seasons in Italy, where he scored 24 league goals as the Nerazzurri clinched their first Serie A title in 11 years last season.
The move marks a return to the European champions for Lukaku, who made 15 appearances for the Blues over two seasons either side of a successful loan spell with West Bromwich Albion in 2012-13.
He was then sold to Everton in 2014 following an impressive loan at Goodison Park, having failed to score a single goal in a Chelsea shirt.