Chelsea shocked plenty of football fans when they announced the return of Romelu Lukaku this month for an eye-watering £97.5m.
The Blues sold the Belgian to Everton back in 2014 for just £28m, before he went on to join Manchester United three years later.
Since then, Lukaku finally realised his potential in the Serie A with Inter Milan, where he helped the Nerazzurri win the title last season.
The 28-year-old is back in the Premier League now though, and is in the absolute prime of his career, which you'd hope given his huge price tag.
It seems to be an absolutely astronomical fee, especially given Chelsea spent over £200m last summer on new signings too.
But Mirror Football breaks down the nine signings Chelsea are set to make before the end of the window that actually left them in profit.
Tammy Abraham - £34m
The biggest sale of the summer at Stamford Bridge, in many ways it seems Chelsea did well to get such a big sum from Roma for a player on the periphery of Tuchel's squad.
Abraham's goalscoring record spoke for itself though, having finished as the joint top scorer for the Blues last season, despite starting just 12 Premier League games and not appearing in the Champions League after the group stage.
Fikayo Tomori - £26m
Letting such a promising player like Tomori leave is always a huge gamble, especially given that he barely put a foot wrong in a Chelsea shirt.
Was it a good move by Chelsea to sell all these players and bring back Lukaku? Have your say in the comments section
But a big fee from AC Milan was always going to tempt the Blues into selling a player who was struggling to get into the first team, and this seems like a good deal for both parties.
Marc Guehi - £20m
Another young, English centre-back to depart is Guehi, who made just two Carabao Cup appearances with the senior team at Chelsea.
The 21-year-old was highly impressive at Swansea on loan last season, and he is set to go on to become an important player for Crystal Palace this term after starting against Chelsea last weekend.
Kenedy - £8.5m (not confirmed)
Brazilian winger Kenedy arrived at Chelsea six years ago with plenty of hype behind him.
However, the 25-year-old has spent the bulk of his time out on loan, and is now believed to be close to sealing a move back to Fluminense for £8.5m.
Tino Livramento - £5m
Not a name those who don't follow Chelsea will have heard of much, Southampton showed some serious intent when they snapped up Livramento for £5m earlier this summer.
The 18-year-old started their first game of the Premier League season too, meaning the right-back could play a starring role on the south coast this year.
Victor Moses - £4.5m
Yes, the time has finally come - after a nine-year spell in west London, Moses has finally left the club, and for a handsome fee of £4.5m too.
Having spent last season on loan at Spartak Moscow, the Nigerian decided to make the move to Russia permanent, and will be hoping to become a little more settled now he's into his thirties.
Lewis Bate - £1.5m
A much talked about youngster at Chelsea, Leeds snapped up the 18-year-old earlier this summer for a mere £1.5m, and he has gone straight into their U23 set-up.
Bate did not make a first team appearance at Chelsea, but he would surely have been in the pipeline soon if he had not been loaned out.
Dynel Simeu - £1.5m
Another export to the Saints, teenage defender Simeu also seemed keen to avoid falling into the Blues' never-ending loan system by leaving for Southampton permanently.
The England youth international looks set to have a promising career ahead of him, and Chelsea could regret letting him go for such a low fee.
Olivier Giroud - £1m
Rounding off the list, Giroud's exit was one of the reasons Chelsea needed to bring in a new striker, with Tuchel short on attacking options.
The Frenchman's switch to AC Milan is likely to be his last, with the 2018 World Cup winner now 34, but he will always be looked back on fondly by Blues fans.
