Dickens was enamoured by the theatre.  He thought of becoming a professional actor and acted in many amateur productions (often of his own devising).  Many of his acquanintances commented on the histrionic nature of his personality.  In public, Dickens was always performing.

One can really see the theatrical nature of Dickens in the very structure of the chapters in Pickwick.  Many of them begin with a “setting of the scene,” in which Dickens paints the backdrop for us:  “In the ground floor of a dingy house . . .” begins Chapter XX about Mr Pickwick’s visit to the office of the “mean, rascally, pettifogging robbers” Dodson and Fogg.  Then Dickens further paints the scenery: the furniture, the walls, the windows, the placement of the characters.  It’s like he’s telling the set designers how to dress the stage.  (This is perhaps why Dickens has been filmed so often.  He’s alrady done much of the work for the director.)  This setting is usually accompanied by the musings of the narrator, as if an actor is reciting a prologue before the main action begins.  Then on come the actors spouting their lines.  Another example of this theatrical structure is Chapter XIX, in which we have a kind of narrator’s prologue, the setting, then the actors and their lines.