Chelsea's considerable success in the last 20 years or so can be partly attributed to the significant amount of money they have spent in the transfer market. Indeed, the Blues have never had any issue splashing the cash on talented players, especially after Roman Abramovich took control of the club in 2003.
While there have been some notable flops, many new signings played a pivotal role in an unprecedented era of success for the club featuring Premier League triumphs, two Champions League wins and five FA Cup successes.
Abramovich may now be gone but Chelsea's new owners, a consortium fronted by Todd Boehly, have already demonstrated their willingness to continue spending big, as underlined by the signing of Raheem Sterling, who was brought in from Manchester City to fortify their attack in a deal worth around £50 million ($60m).
Here, GOAL takes a look at the 15 most expensive signings in the Blues' history…
Note: All figures are taken from Transfermarkt unless stated otherwise
#15 Tiemoue Bakayoko | £36m | Monaco | 2017
An integral part of the Monaco side that won the Ligue 1 in 2016-17, Bakayoko had seemingly got his dream move when Chelsea made him their second-most expensive signing of all time in the summer of 2017. The box-to-box midfielder was expected to slot into the Blues' starting line-up seamlessly as they tried to build on their Premier League-winning campaign.
But the Frenchman failed to impress during a season which ended with Chelsea dropping out of the top four. His poor form meant Bakayoko was sent on loan to AC Milan in August 2018. Bakayoko, still contracted to Chelsea, has been on loan continuously ever since, at Napoli, Monaco and Milan again.
He has seemingly found his feet during his second stint at San Siro, helping the Rossoneri win the Serie A last season.
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#14 Hakim Ziyech | £36m | Ajax | 2020
The talented Moroccan arrived in West London in the summer of 2020 after a remarkable spell at Ajax. The attacking midfielder was meant to add a bit of technique and finesse to Chelsea's attack under Frank Lampard.
But Ziyech hasn't quite managed to nail down a spot in the starting XI, even under current manager Thomas Tuchel.
After two full seasons at the club, Ziyech's future at Stamford Bridge remains unclear. Safe to say that the move has not quite worked out, neither for the club nor the player.
#13 Andriy Shevchenko | £39.5m | AC Milan | 2006
Another Chelsea signing which did not turn out as expected at all. The Ukrainian had established himself as arguably the finest forward in the world during his prolific spell at AC Milan, so Abramovich thought he had pulled off a major coup when he managed to sign the striker in 2006.
But Shevchenko never managed to hit the same heights at Stamford Bridge, scoring just 22 goals in 77 appearances. Eventually, he went back to Milan on loan in 2008 before joining Dynamo Kyiv a year later.
#12 Mateo Kovacic | £40.5m | Real Madrid | 2019
The Croatian is an integral part of the Chelsea midfield these days. He joined Chelsea from Real Madrid in 2018, initially on a season-long loan.
Though his first season was nothing to write home about, the Blues decided to sign him permanently under new manager Frank Lampard in 2019. And that decision has been vindicated, with Kovacic a key member of the Chelsea side that won the 2021 Champions League.
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#11 Ben Chilwell | £45.2m | Leicester City | 2020
Having established himself as one of the best left-backs in England, it was not a surprise to see Chelsea spend big on the Leicester City youth product in the summer of 2020.
He had a great first season at Chelsea, making 42 appearances in all competitions. He played the entire 90 minutes as Chelsea beat Manchester City in the 2021 Champions League final.
Though a cruciate ligament injury curtailed his 2021-22 season campaign, Chilwell is already back in Thomas Tuchel's starting line-up and will be battling out with new signing Marc Cucurella for a starting spot this term.
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#10 Timo Werner | £47.7m | RB Leipzig | 2020
Signed for big money on the back of a prolific season for RB Leipzig, Timo Werner's move to Chelsea has not gone well, with the Germany international now tipped to return to his former club.
Werner cut a frustrated figure right from the off, his confidence clearly affected by a succession of glaring misses. He slowly fell out of favour, as Chelsea desperately searched for more dependable attacking outlets.
In fact, there was a marked decrease in his game-time in the 2021-22 season and has long been linked with a move away from Stamford Bridge.
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#9 Raheem Sterling | £50.6m | Manchester City | 2022
The former Manchester City winger has only just arrived at the Bridge and is expected to add a cutting edge to an attacking unit that struggled for goals a bit last season.
Despite falling out of favour a tad during the final year of his time at the Etihad, Sterling's quality cannot be questioned.
He won four titles at City, scoring 131 goals in all competitions, and also played a pivotal role in England's run to the final of Euro 2020.
Given he's still only 27, Sterling could well prove one of Chelsea's best-ever buys.
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#8 Jorginho | £51.3m | Napoli | 2018
Despite being wanted by Pep Guardiola at Man City, Jorginho ended up joining his former Napoli boss, Maurizio Sarri, in West London.
However, while Chelsea won the Europa League in his first season, the cultured midfielder did not have a great first season, as the team struggled under Sarri.
Jorginho, however, did start to live up to his billing in the following seasons, under Frank Lampard and then Thomas Tuchel.
He is a trusted member of the team now, as reliable as his famous 'Hop, skip and jump' penalty technique.
#7 Fernando Torres | £52.7m | Liverpool |2011
Torres' shock move to Chelsea in January 2011 was one of the biggest transfers in Premier League history. The Spaniard had established himself as one of the most feared strikers in the world during a sensational spell at Liverpool. However, he never looked at home at Stamford Bridge.
While he failed dismally to replicate his fearsome Anfield form, Torres still managed to score some big goals, most notably on a famous night at Camp Nou in 2012, and ended up winning the Champions League, Europa League and FA Cup at Chelsea.
#6 Christian Pulisic | £57.6m | Borussia Dortmund | 2019
Pulisic was one of the best young players in Europe when Chelsea snapped him up in January 2019.
However, the American has blown hot and cold during his three years in the Premier League to date.
While capable of producing stunning moments on his day, Pulisic has struggled to deliver on a consistent basis, with his cause not helped by incessant injury issues.
Consequently, despite being Chelsea's youngest hat-trick scorer, the United States international has failed to nail down a spot in the starting XI.
#5 Marc Cucurella | £58.8m | Brighton | 2022
A product of La Masia, Cucurella had looked set to join Manchester City but the Premier League champions were unable to agree a fee with Brighton for a player who had excelled during his debut season at the Amex, in 2021-22.
Chelsea swooped in, picking up a high-quality replacement for the Barcelona-bound Marcos Alonso. The size of the fee has surprised many, though, given the Blues still have Chilwell on their books, even if the England international has only just returned to full fitness after a serious injury.
It remains to be seen, then, if Cucurella will prove worth such a significant outlay.
#4 Alvaro Morata | £59.4m | Real Madrid | 2017
When it comes to signing strikers, Chelsea don't have a particularly good record, resulting in talk of 'The curse of the No.9'. Alvaro Morata is one of the most high-profile victims.
The Spaniard arrived from Real Madrid for big money and with a fine reputation. However, he struggled to adapt to the rigours of the Premier League.
His profligacy became a massive talking point, too, he ended up leaving the club for Atletico Madrid after an initial loan spell at the Wanda Metropolitano.
Chelsea did, at least, manage to recoup most of their original outlay on him.
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#3 Kepa Arrizabalaga | £72m | Athletic Club | 2018
When Thibaut Courtois left Chelsea for Real Madrid in 2018, the Blues had no qualms about making Kepa Arrizabalaga the costliest goalkeeper in history.
Kepa had built up quite the reputation for himself in Bilbao and had even been linked with Madrid six months before arriving in London.
He started off well in the Premier League but then things started to go wrong. A series of high-profile errors and a public spat with Maurizio Sarri in the 2019 League Cup final, when he refused to be substituted, meant his stock plummeted. He was benched for Willy Caballero for the 2019-20 season.
Eventually, Chelsea brought in Edouard Mendy while Kepa became the club's second-choice goalkeeper. A quite expensive one at that!
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#2 Kai Havertz | £72m | Bayer Leverkusen | 2020
Kai Havertz became Chelsea's most expensive signing at the time when they spent £72m to prise him away from Bayer Leverkusen. The attacking midfielder was one of the most sought-after young talents in the Bundesliga at the time.
At Chelsea, the German has sporadically shown his quality, though he is yet to blossom completely. He did give Chelsea their most memorable moment in recent times, though, scoring the winner against Manchester City in the 2021 Champions League final, which, incidentally, was his first goal in the competition.
Still only 23, the technically gifted player has enough time to justify his transfer fee.
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#1 Romelu Lukaku | £101.7m | Inter | 2021
As already mentioned, Chelsea have had rotten luck with signing high-profile strikers and Romelu Lukaku represents just the latest chapter in this sorry story.
Lukaku, who was first, acquired way back in 2011, had been in stunning form in Serie A with Inter. And Chelsea, desperately seeking a goalscorer to lead their attack, made the Belgian their club-record signing in the summer of 2021.
However, despite a bright start, Lukaku struggled to adapt to Tuchel's requirements. The goals dried up and Lukaku did not help his cause by publicly stating his desire to go back to Italy.
After being left out of the squad by Tuchel, Lukaku worked his way back in but never quite convinced. The Belgian did get his wish after all as Chelsea allowed him to re-join Inter on loan for the 2022-23 season.