The Ivory Coast striker has penned a one-year deal with the Blues, completing a return to Stamford Bridge after leaving in the summer of 2012.
"He's coming because he's one of the best strikers in Europe," Mourinho told the club's official website.
"I know his personality very well and I know if he comes back he's not protected by history or what he's done for this club previously. He is coming with the mentality to make more history."
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