Gilbert prepared meticulously for each new work, making models of the stage, actors and set pieces, and designing every action and bit of business in advance. He would not work with actors who challenged his authority. George Grossmith wrote that, at least sometime, "Mr. Gilbert is a perfect autocrat, insisting that his words should be delivered, even to an inflection of the voice, as he dictates. He will stand on the stage beside the actor or actress, and repeat the words with appropriate action over and over again, until they are delivered as he desires them to be." Even during long runs and revivals, Gilbert closely supervised the performances of his plays, making sure that the actors did not make unauthorised additions, deletions or paraphrases. Gilbert was famous for demonstrating the action himself, even as he grew older. Gilbert himself went on stage occasionally, including several performances as the Associate in "Trial by Jury", as substitute for the injured Kyrle Bellew in a charity matinee of "Broken Hearts", and in charity matinees of his one-act plays, such as King Claudius in "Rosencrantz and Guildenstern".