Was 95% of Natalie Portman's Dancing in Black Swan Done By a Body Double?

Natalie Portman has been widely lauded for her transformation into a ballerina for her role in Black Swan. But is Hollywood bullshitting us? Sarah Lane, the professional dancer who worked on the film as Portman’s “dance double,” is speaking out, saying she did most of the dancing in the film. For the dance sequences in question, Portman’s head was apparently digitally grafted onto Lane’s body.