Chelsea's most successful period in their history has come under the now immediate owner, Roman Abramovich.
The Billionaire was been at the helm of the club for the past 19 years, a period in which the Blues won all trophies on offer.
The Russian's billions enabled the London club to compete with the elite, signing the very best in the sport.
Over the years, he has pumped millions into signing the best players in the game, and we take a look at the most expensive players during that time.
6. Fernando Torres - £50m 🇪🇸
The Spaniard became the club's all-time expensive player when he joined the Blues in January 2011 from Premier League rivals Liverpool for £50m.
He struggled to hit the same levels he had at the Merseyside club, scoring just seven goals in his first 46 league games.
This was a stark contrast with his form at Anfield, where he had notched 65 league goals in just 102 games.
He will however be remembered for that goal against Barcelona in the Champions League second leg match at Camp Nou as the Blues went on to win their first-ever crown.
5. Christian Pulisic - £57.6 million 🇺🇸
Believe it or not, the American is in the top five of most expensive players signed during the Abramovich era.
The 23-year-old was signed from Borussia Dortmund in January 2019 in a deal worth £57.6 million.
He is yet to live up to expectations, with constant injuries hampering his development greatly.
Despite his struggles, he has shown he can grow into an important player for the Blues.
He was instrumental in Europe last season as the Blues went all the way, scoring some crucial goals in the process.
In total, he has scored 21 goals in 100 games for the London club.
4. Alvaro Morata - £60m 🇪🇸
Chelsea broke their transfer record once again in July 2017, this time signing Spaniard forward Alvaro Morata from Real Madrid.
The striker had impressed while on loan at Juventus and was signed to lead a new Blues attack alongside the likes of Eden Hazard and Willian.
After a brilliant start, the Spaniard fizzled out and cut a frustrated figure, eventually leaving on loan before permanently signing for Atletico Madrid after just two years in London.
He scored a total of 24 goals in 72 games.
3. Kepa Arrizabalaga - £71m 🇪🇸
After losing Thibout Courtois to Real Madrid, Chelsea were in the market for a new goalkeeper, and they spotted Kepa Arrizabalaga at Athletic Bilbao.
Sensing their desperation, Bilbao put them in a take-it-or-leave-it situation, eventually forcing the Blues to fork an astronomical £71m.
He was seen as a perfect Petr Cech replacement, but after two years of constant mistakes, he was finally replaced by Edouard Mendy at the start of last season.
2. Kai Havertz - £73m 🇩🇪
Havertz made a name for himself in Germany, scoring 46 goals in just 150 games for Bayer Leverkusen.
He was seen as a generational talent and Chelsea won the race to sign him, ahead of the likes of Manchester United, Bayern Munich, and Barcelona.
The youngster has however endured a difficult time, even though he has given the fans moments to celebrate.
He scored the winner in the Champions League final last season and was also on target with the winning penalty in the FIFA Club World Cup.
1. Romelu Lukaku - £98million 🇧🇪
Lukaku got a chance for a second chance at Stamford Bridge after Chelsea failed to convince Erling Haaland to join them.
The Belgian started brightly, scoring in his debut at the Emirates, but has since struggled to score in a number of matches, with many questioning his suitability in the Thomas Tuchel team.
So far, the striker has 11 goals from 30 appearances in all competitions.