'House of the Dragon': Milly Alcock Describes Dynamic Between Siblings Rhaenyra and Daemon Targaryen

Fabien Frankel and Milly Alcock chat with ET about 'House of the Dragon,' the prequel series to 'Game of Thrones.' The actors tease what fans can expect from their characters and whether they were fans of 'GoT' before joining the spinoff. 'House of the Dragon' debuts Aug. 21 on HBO.