Kit Harington joins ‘Harry Potter’ Season 2 as Gilderoy Lockhart

Game of Thrones star Kit Harington has joined the cast of HBO's Harry Potter television series and will play Gilderoy Lockhart in its second season, stepping into the role after Nicholas Hoult exited because of scheduling conflicts.

Harington, best known globally for playing Jon Snow in Game of Thrones, will portray the vain and publicity-obsessed Defence Against the Dark Arts professor when the television adaptation moves into the events of Harry Potter and the Chamber of Secrets.

The casting brings Harington back into the HBO fold and also reunites him with a character he has played before. The British actor previously voiced Lockhart in Audible's full-cast adaptation of Harry Potter and the Chamber of Secrets.

Hoult had been announced for the role earlier but subsequently withdrew because of conflicts with other commitments. Harington will now take over one of the most prominent new characters introduced during Harry's second year at Hogwarts.

From Jon Snow to Lockhart

The role marks a considerable tonal shift for Harington, whose breakthrough performance as Jon Snow made him synonymous with the sombre and battle-hardened world of Game of Thrones.

Gilderoy Lockhart is almost the opposite. The bestselling author and celebrity wizard arrives at Hogwarts with an enormous ego, a fondness for attention and an exaggerated reputation for heroic adventures.

His carefully constructed public image gradually unravels during Chamber of Secrets, making him one of the story's major comic characters.

Kenneth Branagh famously portrayed Lockhart in the 2002 film Harry Potter and the Chamber of Secrets. Harington will now have the opportunity to develop a fresh interpretation in HBO's longer television format.

His familiarity with the character could help with that transition. Harington was among a large ensemble of performers recruited for the full-cast audio adaptations of JK Rowling's novels and had already performed Lockhart's distinctive personality through voice acting.

Season 2 to adapt ‘Chamber of Secrets’

HBO's second season will adapt Harry Potter and the Chamber of Secrets, the second instalment in Rowling's seven-book series.

The story follows Harry's return to Hogwarts as a mysterious series of attacks leaves students petrified and raises fears that the legendary Chamber of Secrets has been opened.

Lockhart joins Hogwarts as the new Defence Against the Dark Arts teacher and initially impresses many students with stories of his supposed exploits. His actual abilities, however, prove considerably less impressive than his celebrity persona suggests.

The television adaptation is being developed as a long-form retelling of the novels, allowing considerably more screen time for characters, subplots and details that could not be accommodated in the original films.

New Hogwarts ensemble takes shape

The new Harry Potter series features Dominic McLaughlin as Harry Potter, Arabella Stanton as Hermione Granger and Alastair Stout as Ron Weasley.

The adult cast includes John Lithgow as Albus Dumbledore, Janet McTeer as Minerva McGonagall, Paapa Essiedu as Severus Snape and Nick Frost as Rubeus Hagrid.

Francesca Gardiner serves as showrunner, while Succession director Mark Mylod is among the project's key creative figures. The series is being produced as a fresh adaptation rather than a continuation of the eight-film franchise.

HBO has already renewed the show for a second season even before the first instalment reaches audiences, reflecting the scale and long-term nature of the project.

The first season, based on Harry Potter and the Philosopher's Stone, is scheduled to premiere on December 25, 2026.

Harington will consequently not appear as Lockhart until the second season, but his casting gives the upcoming Chamber of Secrets adaptation one of its first major new additions — and places another familiar HBO face inside the halls of Hogwarts.