HBO's the Harry Potter movies are not that old and are critically acclaimed. While the crew of the show has claimed that the show will be even more faithful to the books than the movies, it is only with the recent casting news that the show's unique value started to really make itself apparent.

There is currently an open casting call for the Golden Trio. The trio is Harry Potter, Ronald Weasley, and Hermione Granger, played in the movies by Daniel Radcliffe, Rupert Grint, and Emma Watson, respectively. This suggests an unknown cast for the movie's three main characters, ensuring a fresh start for the TV show and giving new talent a chance to shine. With upwards of 30,000 children having auditioned already, the Harry Potter TV show is sure to find the right talent. Meanwhile, for its adult cast, the show appears to be targeting particular actors.

While the cast hasn't been confirmed, it's been announced by HBO that Succession's sca Gardiner will serve as the showrunner for the Harry Potter TV show, with Mark Mylod as director/executive producer.

Lord Voldemort

Cillian Murphy

Casting rumors for the Harry Potter TV show position Cillian Murphy as a potential candidate for the evil Voldemort. While Hero Fiennes Tiffin played a child Voldemort and Christian Coulson played the character at Hogwarts, Ralph Fiennes represented Voldemort throughout the majority of the Harry Potter movies. Taking over as Voldemort would be a huge job for Murphy, with three excellent actors to compare to. The show would likely require younger versions of the character, just as the movies did, but Murphy would be stepping into a life-changing role nonetheless.

HBO has neither confirmed nor denied the Cillian Murphy rumors.

This Irish actor would make an excellent Voldemort and was even endorsed by Ralph Fiennes himself, who nailed the character in the Harry Potter movies. Fans asked Fiennes what he thought of Murphy playing Voldemort on Watch What Happens Live with Andy Cohen. Fiennes confirmed that "Cillian is a fantastic actor. That’s a wonderful suggestion. [He] would be all in favor of Cillian." However, HBO has neither confirmed nor denied the Cillian Murphy rumors. As such, they are nothing more than hearsay, and the casting of Lord Voldemort remains unknown.

As of early 2025, many outlets (such as SuperHeroHype) are reporting that Cillian Murphy is indeed tied to a role in the Harry Potter TV series, and that role is for a villain, though the current theories are that it isn't Lord Voldemort.

Sirius Black

Ben Barnes

Among the more intriguing Harry Potter TV show cast rumors is the role of Sirius Black who (in theory) wouldn't appear until the series covers the events of the third novel, The Prisoner Of Azkaban. However, the HBO show could include him earlier, since - unlike when the movies were in production - the story of the entire Harry Potter saga is known, and there are definitely opportunities for glimpses of Sirius prior to Harry's third year at Hogwarts.

So far, one name has been strongly attached to the role of Sirius Black in HBO's Harry Potter show - English actor Ben Barnes. Barnes is certainly no stranger to magical tales like Harry Potter, having starred in The Chronicles of Narnia movies and the Netflix series Shadow and Bone. However, while this particular Harry Potter TV show cast rumor is mainly driven by fans, Barnes did speak to US Magazine to give his thoughts on the prospect:

“You wouldn’t believe the amount of Harry Potter books I’ve signed or Gryffindor scarves I’ve been given as gifts, the amount of fan fiction that I’ve been drafted into very enthusiastically is incredible. It’s been going on for 20 years that people have been very kindly saying that they would’ve liked me to have played a young version of the Sirius Black character in Harry Potter, but now it’s been going on so long that I’m now the age of the actual character in the books. They’re books that I love and at least half of my career has been based on literary adaptations that I’ve loved. And [Harry Potter], I see no reason why it would be any different, but I haven’t spoken to anyone about it yet.”

Minerva McGonagall

Rachel Weisz

Rachel Weisz's name has been tossed in the ring for the role of Minerva McGonagall. As far as Hogwarts heasters in Harry Potter go, McGonagall is one of the most beloved. McGonagall was the head of Gryffindor and the Transfiguration Professor before Dumbledore died in Harry Potter and the Half-Blood Prince. After Dumbledore's death, McGonagall ascended to heistress, making her one of the most powerful witches in the world of Harry Potter. Rachel Weisz has a history of playing incredibly powerful women, so she would probably play McGonagall perfectly.

Deadline reported conflicting information on the casting of Rachel Weisz as Minerva McGonagall without citing a source. It appears that Weisz is being discussed in relation to the role at an industry level. However, there is little to point to whether this rumor is closer to a fancast or a serious conversation. Seemingly, Rachel Weisz fans must wait to know if she will be put forward for the huge role or not. If not, there are other actresses being considered for the role who may also handle it with aplomb.

Sharon Horgan

Deadline hinted that Sharon Horgan may end up playing Professor McGonagall in the Harry Potter TV show. Along with Dave Finkel and Brett Baer, Horgan developed the comedy TV show Bad Sisters, which was met with significant commercial success. The Irish actress and director has astounding comedic timing, both as a showrunner and on-screen. It is uncertain if she would be welcomed as Professor McGonagall by the world at large, since she is relatively unknown. However, she does seem like she has the acting chops to play the world's most-loved transfiguration professor.

Maggie Smith voiced Minerva McGonagall in the Harry Potter video game Harry Potter: Hogwarts Mystery.

In being cast in the Harry Potter TV show, Horgan would be filling the shoes of Dame Maggie Smith, the last person to play Professor McGonagall on screens. Maggie Smith was the perfect Professor McGonagall in every way, which is part of what made it so affecting for so many when she ed away in September 2024. As McGonagall, Smith was prim, proper, warm, and morally upstanding, somehow embodying British stereotypes and rejecting them all at the same time. Smith's mild Scottish accent had a strong impact on her characterization of McGonagall, which Horgan's Irish heritage may see her emulating in some way.

Rubeus Hagrid

Brett Goldstein

Rubeus Hagrid was masterfully portrayed by Robbie Coltrane in the Harry Potter movies, but Brett Goldstein may be seeking the Hagrid role for the TV show. This British actor is in some big movies, but may be best known for his stand-up comedy. This points to HBO moving toward actors wired for the stage for their adult cast. The Potterverse movies tended toward stage actors for their adult casts. This helped them capture the grandiose nature of their characters, who were pulled from fantasy children's books with huge scope, ranging from comedy to horror.

The Harry Potter movies can be streamed on Peacock in the U.S.

Indeed, Brett Goldstein's stage experience may help him acclimatize to the role. Although he isn't widely known as a theater actor, like many of the Harry Potter movies' cast, he actually has perfect stage experience for Hagrid. Hagrid was often the comic relief when the Harry Potter movies got dark, and he will likely provide a similarly essential role in the HBO TV show. Ted Lasso actor Brett Goldstein won a Primetime Emmy Award for Outstanding ing Actor in a Comedy Series. Along with his stand-up comedy experience, this proves that Goldstein could handle Hagrid.

Severus Snape

Paapa Essiedu

Paapa Essiedu is strongly rumored to be eyed for the role of Severus Snape in the Harry Potter TV show. This British actor played Kwame in Michael Coel's critically acclaimed I May Destroy You. This serious and moving drama touching on the topic of consent required incredible depth from all its cast. Essiedu, in particular, delivered unbelievable confidence and angst in I May Destroy You. Anyone who has seen it could probably testify to his ability to play Severus Snape with serious flair. And, this casting rumor is fairly well-founded.

Production of the Harry Potter TV show is set to start in the summer of 2025.

Unconfirmed sources told The Hollywood Reporter that Paapa Essiedu is being tapped for the Snape role. HBO was ed for comment and said "As we make our way through pre-production, we will only confirm details as we finalize deals.” The subscription television service neither confirmed nor denied the claims, so it seems like Essiedu stands out as a likely contender for the new Severus Snape. However, a deal would have to be finalized between HBO and the actor for Snape's casting to be completed. Such a high-profile show could secure another perfect choice for Snape if Essiedu did not .

Albus Dumbledore

John Lithgow

One of the latest casting rumors for HBO's Harry Potter TV show is one of the most interesting, and sets apart the show from the movies in a key way. The original Harry Potter films had strict rules about casting talent from the UK, though - if the rumors are to be believed - this clearly isn't the case with HBO's show. This is evidenced by the fact that the latest actor rumored to play Albus Dumbldore is American actor John Lithgow of Dexter, Interstellar, and Conclave fame.

The rumors about John Lithgow playing Dumbledore began circulating in mid-February 2025. However, according to outlets like E News!, neither HBO or Lithgow have confirmed or denied the casting. When the John Lithgow Dumbledore news first broke, there was intense speculation that the actor was on the verge of g a contract with HBO, and was incredibly close to being casted. However, until this is confirmed or denied by Lithgow or HBO themselves, it's still entirely speculative.

John Lithgow is certaintly an interesting casting choice for Albus Dumbledore, and very different to the late Richard Harris or Michael Gambon (who portrayed them in the Harry Potter movies). Should this Harry Potter TV show casting rumor turn out to be true, it guarantees that the cast of the TV series will have a very different feel to the films.

Mark Rylance

Mark Rylance was one of the first rumors to emerge from the rumor mill when it came to the casting of the Harry Potter television series. Rylance may end up playing Hogwarts Heaster Albus Dumbledore. This British theater and movie actor has incredible range, playing scary roles as often as he plays kindly ones. Rylance was both terrifying and sweet in Bones and All, the underrated Luca Guadagnino drama starring Timothée Chalamet. The serial killer vampire had the veneer of a wizened and caring old man, and somehow this would transpose perfectly to the profoundly layered Albus Dumbledore.

Also, Mark Rylance's experience with the Royal Shakespeare Company would prepare him for the role of Albus Dumbledore. Michael Gambon and Richard Harris both had significant theater experience, which was clear in their performances as Dumbledore. The flamboyance and hugeness of a leading stage role was evident in both versions of Dumbledore, which bore a striking resemblance, despite bringing their own flavor to the movie franchise. Rylance, who has starred in The Other Boleyn Girl and Bridge of Spies, could continue this trend, with a dramatic Dumbledore and gigantic gravitas.

Mark Strong

The newest Dumbledore rumor to emerge is around Mark Strong, the phenomenal British actor well-known for his roles in Tinker Tailor Soldier Spy, Shazam!, and Sherlock Holmes. While Mark Rylance is a fantastic option for Albus Dumbledore, Mark Strong is an equally brilliant and high-profile proposition. HBO is reportedly looking to make a decade-long series, so the role of Dumbledore would be completely defining for whoever took it up. With a fantastic career already behind him, the well-known Mark Strong appears more than ready to assume this colossal responsibility.

It seems like HBO has not yet made Mark Strong a formal offer of the role. When pushed on the status of the Albus Dumbledore role and on which actor may pick it up, HBO responded that they would only confirm details as they finalize deals. This is the same reply they provided in response to being asked about Paapa Essiedu ing the show as Snape, and looks to represent their overarching statement on all casting matters for the time being. Fans will have to wait to find out which Mark won the Dumbledore role in Harry Potter, if any.

Source: Watch What Happens Live with Andy Cohen, Deadline, The Hollywood Reporter