Heather Morris (Brittany) had actually met Britney Spears a couple of years earlier before shooting this episode. Morris auditioned for the singer in a dance submission dressed up like her and singing like her for a choreographer, which Britney stated "You were perfect for me".
According to Vulture, Heather Morris (Brittany) says Ryan Murphy asked her to take vocal lessons to prepare for this episode.
While Rachel is still feeling the effects of the anesthesia at the dentists, she asks "Is this real life?", a reference to the popular 2009 youtube video "David After Dentist".