Welcome to the Premier League, Thomas Tuchel.
The former Paris St-Germain boss takes over as manager at Stamford Bridge from Frank Lampard, after the club's all-time record goalscorer was sacked.
Tuchel, himself shown the door by PSG in December, was called one of European football's most complex managerial personalities by German football expert Constantin Eckner.
How familiar are you with the 47-year-old German coach?
Take the quiz below to find out if you are a Tuchel know-all...
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Source: bbc.com