The German coach has officially taken over at Stamford Bridge and will be on the bench for Wednesday’s game against Wolves.
But he will not be officially unveiled to the media until later this week after Chelsea spent Tuesday finalising the terms of his deal.
Chelsea’s hierarchy had identified Tuchel as Roman Abramovich’s 11th permanent managerial appointment some time before Frank Lampard’s sacking on Monday morning.
They wanted to ensure the former Paris Saint-Germain manager would be in place in time for the visit of Wolves before making Lampard’s departure official.
That was delayed as a result of Brexit and Covid-19 regulations, but after arriving in London, Tuchel has been cleared to join Chelsea’s bubble at Cobham, which means he will be able to sit in the dugout and begin a new era at Stamford Bridge on Wednesday.
While the 47-year-old will have to adhere to UK quarantine rules, he has been granted an exemption by the FA to take charge of Chelsea immediately after testing negative for coronavirus.
Tuchel has been left in no doubt about the expectations of him in his new role.
Lampard was sacked after failing to meet his pre-season remit of closing the gap at the top of the table.
The club made it clear to the legendary former midfielder last summer that a top four finish was not an acceptable minimum requirement.
There were concerns about his lack of experience – and lack of a plan going forward.
The form and confidence of a squad that the club’s hierarchy believe is capable of challenging at the top of the table, was also a factor.
Tuchel will be expected to turnaround the fortunes of expensive summer recruits and compatriots, Kai Havertz and Timo Werner. But it is understood issues within the playing staff went beyond that duo.
He has been charged with the responsibility of salvaging a season that sees the club still in the Champions League and FA Cup - and just 11 points off top-of-the-table Manchester United.