Hynek Cermák and Viktorie Cermáková, who play a married couple in the film, are brother and sister in real life. Besides acting together naked in the shower scene, they also have an erotic scene. "I talked to the director before filming about the fact that he should rather cast me and my brother in the role of the tired couple, so that I don't have to play the passion with my brother," Viktorie said. For his part, Hynek said he was not reluctant to play his own sister's husband: "I don't mind immorality, so I didn't hesitate." But he said he was not very comfortable with the bed scenes with his own sister. "I didn't play anything... but the love scenes with my own sister... that was probably the most difficult thing I've ever done as an actor," he said.