"He's one of the best defenders on the planet," said Ancelotti. "I'm really very happy with the arrival of Thiago Silva.
"He's a fantastic player and the whole world knows that he's one of the greatest. With him, as well as the others, we could have a very valid defence.
"I know Thiago well because I coached him for six months at Milan and he can certainly improve our defensive strength.
"The club have done some great work to bring in such a champion."