The exteriors of Orlok's castle were filmed at Hunedoara Castle, also known as Corvin Castle, a Romanian castle located in Transylvania and one of the largest medieval castles extant in Europe. What's more, it's the castle where Vlad Dracula was briefly imprisoned.
According to Bill Skarsgård, his voice was the aspect of the part he worked hardest at, spending six weeks before shooting not doing 'much else than just record myself'. 'And on set, I would keep doing these exercises. It sounds kind of like Mongolian throat-singing. It's [insane].'
The castle scenes were filmed in the Pernstejn Castle in the Czech Republic, the same location that was used for Werner Herzog's film Nosferatu the Vampyre (1979).
Bill Skarsgård was originally cast as Thomas Hutter. However, during the film's long pre-production development, director Robert Eggers decided to recast Skarsgård as Count Orlok/Nosferatu, instead. In an interview with Skarsgård, Eggers stated that he felt that the recasting was to make the sexual subtext between Orlok and some of his victims even more convincing.
Producer Chris Columbus said Bill Skarsgård was so terrifying in costume that he couldn't even approach him on the set. That is until Skarsgård made everyone laugh. Then, Columbus "knew Nosferatu had a sense of humor."