 In the episode where Carrie is invited to Mr Big and Natashas  engagement party, the props department decided to make up a first  name for the character to appear on the invitation, knowing that it  would never appear on screen. Sarah Jessica Parker (qv) opened the  envelope to find she had been invited to the wedding of "Boris and  Natasha" (named after the villains in  _"Rocky and His Friends" (1959)_ (qv)), she reportedly couldnt stop  laughing for five minutes.