Kai Havertz has left the Germany national training camp to complete a club record move to Chelsea, the German Football Association have confirmed.
The Bayer Leverkusen midfielder will travel to London to undergo a medical after a £70m fee was agreed, plus add ons.
The deal, which will top Chelsea's previous record fee of £71m for Kepa Arrizabalaga, is expected to go through in the next 24 hours.
Havertz was an unused substitute during Germany's Nations League clash with Spain on Saturday, with both clubs expecting him to be left on the bench to avoid injury.
The 21-year-old will become Chelsea's seventh signing of the summer.
Havertz is understood to have agreed personal terms weeks ago.
Leverkusen manager Peter Bosz admitted earlier this week that his star man was unlikely to train with his side again after leaving for international duty.
"Unfortunately our squad isn't set yet,” he said. “I don't expect (Kevin) Volland and Havertz to train with us again.
“It's possible more players will transfer. We definitely still have to add some players.”
The fee takes the Blues’ summer spending well above £200m, having already snapped up another six players who will all be sniffing around the starting XI.
Lampard’s first signing was Ajax winger Hakim Ziyech, who cost a relatively risk free £37m.
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He was followed through the door by top German striker Timo Werner, joining from RB Leipzig for £47.5m.
Chelsea have also tied down Leicester left-back and long-term target Ben Chilwell for £50m.
And finally joining on free transfers, centre-backs Thiago Silva and Malang Sarr arrive from playing regularly in France last year.