Thomas Tuchel has said it feels "amazing" to be Chelsea's manager after his appointment was confirmed on Tuesday.
Following a run of five defeats in eight Premier League games, Frank Lampard was sacked on Monday after a year and a half in charge of the Blues.
The club moved swiftly to replace the Chelsea legend, with Tuchel on the market following his own sacking by PSG last month.
Tuchel was confirmed as Chelsea's new manager on Tuesday, as the German signed an 18-month contract with the option of a further year in west London.
After taking over at Stamford Bridge, the former Mainz and Borussia Dortmund manager said he couldn't wait to get started.
"I would like to thank Chelsea FC for their confidence in me and my staff," Tuchel told the club's website. "We all have the greatest respect for Frank Lampard’s work and the legacy he created at Chelsea. At the same time, I cannot wait to meet my new team and compete in the most exciting league in football.
"I am grateful to now be part of the Chelsea family - it feels amazing!"
Chelsea director Marina Granovskaia added: "It is never easy to change head coach in the middle of the season but we are very happy to secure one of Europe’s best coaches in Thomas Tuchel. There is still much to play for and much to achieve, this season and beyond. We welcome Thomas to the club."
Tuchel, whose first match in charge will be on Wednesday against Wolves, will look to get the Blues back into the race for the top four with the club currently languishing in ninth in the table.
Chelsea have also advanced to the Champions League last 16, where they will take on Atletico Madrid over two legs in February and March.
Tuchel nearly led PSG to the Champions League title last season, taking the Ligue 1 outfit to the final where they fell to Bayern Munich 1-0.
Though he fell just short in Europe, Tuchel won six domestic trophies in two seasons after succeeding Unai Emery as PSG head coach in the summer of 2018.