Who is Luke Thallon? Meet the theatre star cast in HBO's upcoming Harry Potter TV series

After months of rumours, the network today (April 15) revealed that John Lithgow will play Albus Dumbledore, Janet McTeer is set to portray Minerva McGonagall, Paapa Essiedu will take on the role of Severus Snape, and Nick Frost will appear as Rubeus Hagrid.

In addition to the main cast, HBO announced that Luke Thallon will join in a guest or recurring role. Currently best known for his theatre work, he is perhaps the least well-known actor of the bunch.

Here’s everything you need to know about the 29-year-old rising star - including where you may have seen him before.

Who is he playing in the Harry Potter series?

Thallon will play Quirinus Quirrell, stepping into a role originally portrayed by Ian Hart in Harry Potter and the Philosopher’s Stone. Quirrell is the first Defence Against the Dark Arts teacher Harry, Ron, and Hermione encounter in their first year at Hogwarts.

Who is Luke Thallon?

Thallon is an actor primarily known for his stage performances. He made his professional debut in Albion, a play by Mike Bartlett at the Almeida Theatre in 2017, while still finishing up at the Guildhall School of Music and Drama.

What has he done before?

Thallon has appeared in a range of theatre productions. He portrayed Roman Abramovich in Patriots, a 2024 play by Peter Morgan, and had multiple roles in Tom Stoppard’s Leopoldstadt in 2020—a performance that earned him the Clarence Derwent Award.

Most recently, he played Hamlet in the Royal Shakespeare Company’s 2025 production, alongside Jared Harris as Claudius and Nancy Carroll as Gertrude. Reflecting on the role, he told Deadline that he cleared his schedule three months before rehearsals to prepare.

"I really would. There’s no pretending that I turn lots of things down, but I’m just waiting for the reason to go to screen to be as exciting and as fulfilling as the things I get to do on stage now," he said about his interest in working on screen.

Thallon has also acted in radio dramas like A Room With A View and The Age of Anxiety, and he made a brief, uncredited appearance in The Favourite.