André Schürrle has completed his transfer to Chelsea from Bayer Leverkusen for an undisclosed fee.
The 22-year-old winger has signed a five-year contract with the Europa League winners and will wear the number 14 shirt.
Schürrle was heavily linked with a move to Stamford Bridge last year when Roberto di Matteo was Blues coach, and Chelsea have retained their interest despite José Mourinho's arrival.
"I am so happy now I have signed and it is an honour for me to play for this club, with this team and for these great fans," Schurrle said. "I am really looking forward to it."
He scored 14 goals for Bayer in all competitions last season as they finished third behind Bayern Munich and Borussia Dortmund.
Capped 24 times by Germany, Schürrle played twice at last year's European Championship and has scored seven times for Die Mannschaft.
Ludwigshafen-born Schürrle will offer Mourinho another attacking outlet aside from Chelsea's vibrant attacking trio of Eden Hazard, Oscar and Juan Mata.
Schürrle's arrival is ominous news for his compatriot, Marko Marin, who agreed to join Chelsea in April last year from Werder Bremen.
Marin, 24, only made five starts for Chelsea last season and an additional 11 substitute appearances.