 Cecil B. DeMille (qv) was actually filming a scene from  _Samson and Delilah (1949)_ (qv) with the actual cast and crew of  that film during Norma Desmonds "visit" to the studio. Actor Henry  Wilcoxon can be seen approaching Norma. The scene of DeMille filming  a "period" film looks convincing because it really was real.