While fans of the wizarding world are still guessing who will play Harry Potter, Ron, and Hermione, the showrunners seem to have already decided on most of the key characters. And one of the most unexpected castings is John Lithgow as Albus Dumbledore.
Lithgow is a legendary actor, twice nominated for an Oscar and a six-time Emmy winner. However, his image in popular culture is strongly associated not with the good wizard, but with the serial killer Arthur Mitchell, known as "Trinity" from the cult series Dexter. It was this role that earned him one of the most creepy and memorable reputations in the history of television.
In addition, Lithgow is remembered by viewers as Winston Churchill in The Crown, and he recently shone in the film Conclave. The actor has repeatedly played British characters, which probably helped him get the role of Dumbledore, despite his American origin.

Interestingly, Dumbledore and Trinity are polar opposites. One is the embodiment of wisdom and kindness, the other is a cold-blooded killer with brutal methodicalness. Perhaps it is this versatility that made Lithgow the perfect choice: he is capable of playing both charismatic leaders and intimidating antagonists.
HBO has not yet officially confirmed the information, but judging by the fact that Lithgow is already in the final stages of negotiations, there is little doubt. The Harry Potter series promises to be a “deep and faithful adaptation of the books,” and it's premiere is expected in late 2026 or early 2027.