In the opening, Kurt performs "Single Ladies (Put A Ring On It)" by Beyoncé with Tina and Brittany as backup dancers. Heather Elizabeth Morris (Brittany) was a back-up dancers for the "Single Ladies" performance with Beyoncé at the 2008 American Music Awards. Morris was actually a back-up dancer for Beyoncé for a year and a half between 2007-2008, and performed live with her for "Single Ladies."
Rachel believes she should get the solo in 'Tonight' because she identifies with Natalie Wood. Wood, however, did not do her own singing in the film of West Side Story (1961) - she was dubbed by Marni Nixon.