Chelsea have re-signed striker Romelu Lukaku from Inter Milan for £97.5m.
The 28-year-old Belgian returns to Stamford Bridge on a five-year deal, having left the Blues to join Everton for £28m in 2014.
The fee is just short of the British transfer record of £100m paid by Manchester City for Jack Grealish.
"I came here as a kid who had a lot to learn, now I'm coming back with a lot of experience and more mature," Lukaku said.
"I have supported Chelsea as a kid and now to be back and try to help them win more titles is an amazing feeling."
More money has now been spent on Lukaku than any other player in history with clubs paying out a combined figure of about £290m in transfer fees for him.
Two of the top five fees paid for a player in British football history have now been for Lukaku.
Belgium's all-time top goalscorer is also the most expensive player ever sold by a Serie A club, having become the third most expensive buy in Italian history when he joined Inter in the summer of 2019 from Manchester United for £74m.
European champions Chelsea finished fourth in the Premier League last season, scoring 58 goals - which was only the eighth-highest total in the division.
German striker Timo Werner, who signed for a reported fee of about £48m in June 2020, contributed just six in 35 league appearances.
Chelsea director Marina Granovskaia said, in Lukaku, they have signed "quite simply one of the world's best strikers and goalscorers".
"We are absolutely delighted to be bringing him back to the club he loves, and are excited to be adding his talent to our Champions League-winning squad," she said.
Lukaku, who helped Inter to the Italian Serie A title last season, said the chance to return "comes at the right time".
"'The way the club is going fits my ambitions perfectly at 28 and just coming off winning Serie A," he added.
"Hopefully we can have a lot of success together."
Despite saying he was happy to stay with the Italian champions, Lukaku reversed his stance earlier this month and told Inter that he wanted to join Chelsea if the right offer was received.
In a short statement confirming the frontman's departure, Inter thanked Lukaku for his two seasons of service and wished him "all the best in his future challenges".
His arrival at Stamford Bridge could prompt the exit of other strikers with Roma and Arsenal interested in 23-year-old England international Tammy Abraham and out-of-favour Michy Batshuayi linked with a move to Turkey.
When Lukaku first arrived at Chelsea he was compared to Chelsea legend Didier Drogba, who he went on to briefly play alongside at the club.
In three seasons as a Chelsea player, however, he scored just one goal in 15 games.
Twice he was sent out on loan by the west London club, featuring for West Brom and Everton before he was eventually sold permanently to the Toffees.
In 2017, he moved to Old Trafford for an initial £75m and, having scored 42 goals in 96 games for United, Lukaku joined Inter.
He scored 64 goals in 95 appearance in his two season at the San Siro, helping the Nerazzuri to a first Scudetto since 2010 in his final term.
"Since I left Chelsea, it's been a long journey with a lot of ups and downs, but these experiences made me strong and the challenge is to try to help the team win some more trophies," added Lukaku.
Chelsea had been heavily linked with Borussia Dortmund striker Erling Braut Haaland, but the German club ruled out selling the 21-year-old Norwegian this summer.
Source: BBC