Chelsea's revolution under Frank Lampard went up another notch on Friday evening as Kai Havertz's £90million transfer was confirmed.
The 21-year-old joins for an initial £71m, plus various add-ons. He has signed a five-year contract.
"I am very happy and proud to be here," Havertz told the club's website.
"For me it is a dream come true to play in a big club like Chelsea and I can't wait to meet all the players and the trainers. Yeah, I am very happy to be here!"
Havertz wasted no time to show off his new colours, with Chelsea posting a picture of their new recruit in kit at Stamford Bridge.
Chelsea owner Roman Abramovich has underpinned a hugely-impressive transfer window for the Blues, with manager Frank Lampard backed to launch a new Stamford Bridge era.
Prolific Germany striker Timo Werner, Ajax's Hakim Ziyech and Leicester's England left-back Ben Chilwell have all arrived in west London in big-money deals.
France Under-21 defender Malang Sarr has huge promise having signed on a free transfer but will head out on loan, while Brazil stalwart Thiago Silva has arrived from Paris St Germain.
The Blues have battled past their transfer ban and losing talisman Eden Hazard to Real Madrid last summer, with new boss Lampard impressing in a challenging first year at the helm.
The former England and Chelsea midfielder secured secured a fourth-place Premier League finish and Champions League qualification in his maiden managerial campaign, and has now received significant backing for his Stamford Bridge squad overhaul.
Additional reporting by Press Association.
