She was friends with Countess Mitzi Wittenmeier. Alfred Stahlbaum, obsessed with the Empress, was hoping that she might take interest in the performances of the Silver Turk, who was in fact a Cyberman named Bremm. He asked Mitzi to drop in a good word for him with her royal friend.
In the end, Sisi sent a letter with Ernst Bratfisch, in which she invited Stahlbaum to attend the Hofburg Palace with the Silver Turk. But the performance did not happen because another Cyberman, Gramm, intercepted Stahlbaum on the way to the palace and took Bremm with him.