Principal ballerina of the San Francisco Ballet Yuan Yuan Tan has been cast in a new role and it's not onstage. The Shanghai-born ballerina appears in the newly-released Gap fall campaign (above) among up-and-coming musicians and dancers.Tan, principal at the SFB since 1997, is also a brand ambassador for Van Cleef & Arpels and Rolex. Let's take a moment to remeber that Gap ad from 2007 with Roberto Bolle (and Greta Hodgkinson of the National Ballet of Canada).