Luiz, who committed himself to the club after yesterday's 1-0 win over Stoke , said he was very happy to sign a deal eith Chelsea.
"I am very happy to sign a new contract. This is a great club and I look forward to winning more trophies here," the Daily Star quoted Luiz, as saying.
"I want to play for a long time at the top level. I love everything about the club and especially the fans, who have made me very welcome," he added.
Luiz, meanwhile, has become something of a mentor and a minder for his fellow Brazilian Oscar.
Nobody was happier than Luiz when Oscar, 21, scored twice on Wednesday, as Chelsea started their defence of the Champions League with a 2-2 draw against Juventus.
After the game, Luiz said: "Oscar will go be one of the world's great players. It is so difficult to defend the Champions League. It is such a hard competition and Juventus showed how hard it is going to be." (ANI )