The 28-year-old hitman finally put pen to paper this morning once chief executive Peter Kenyon got the go-ahead from Roman Abramovich.
The deal should have been struck yestrday but Kenyon had trouble getting hold of Chelsea's owner.
Anelka has signed a four-and-a-half year deal worth £95k a week.
Bolton got £14m out of the Stamford Bridge outfit.
While Anelka is a happy man, Claudio Pizarro's nose has been firmly put out of joint.
The Peru striker had expected to start tomorrow but will have to cool his heels on the bench.
If Andriy Shevchenko shrugs off his latest injury, Pizarro might even be watching from the stands.
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