Tom Riddle is now Billy Barratt's problem

Billy Barratt has been cast as teenage Tom Riddle for Harry Potter Season 2. It is a central role in Chamber of Secrets, where Harry encounters the apparently helpful former Hogwarts student through an enchanted diary.

Barratt has appeared in Bring Her Back, Invasion and Kraven the Hunter and became the youngest winner of the International Emmy for Best Actor for Responsible Child.

The role requires more than looking like a younger Voldemort. Riddle has to work before Harry understands who he is. His charm is part of the mechanism.

Dobby has an actor, but not yet a public final look

Lenny Rush will play Dobby, the house-elf whose increasingly destructive attempts to protect Harry drive a surprising amount of the second book's opening act.

Rush is known for Am I Being Unreasonable?, Dodger and Enola Holmes 2. HBO has not yet shown how its version of Dobby will look or detailed how the character will combine Rush's performance with visual effects.

The films used Toby Jones as Dobby's voice. The television adaptation now has an opportunity to build its own physical and vocal version of one of the franchise's most recognizable non-human characters.

Ginny Weasley changes between Year 1 and Year 2

Bonnie Hill will take over as Ginny Weasley beginning with Season 2. Gracie Cochrane, who already filmed the role for Philosopher's Stone, remains in Season 1.

Cochrane's family previously said she had made the difficult decision to leave because of unforeseen circumstances. HBO publicly supported the departure.

The timing makes the recast particularly visible. Ginny is a relatively small presence during Harry's first year. Chamber of Secrets makes her indispensable to the season's central mystery, so Hill will effectively arrive just as the character becomes dramatically important.

She also becomes the second actor named Bonnie to play Ginny Weasley after Bonnie Wright in the original films. A small coincidence, but an unusually tidy one.

HBO is building Chamber of Secrets before Philosopher's Stone airs

Season 1 premieres December 25 on HBO and HBO Max, yet production planning for the second book is already well underway.

That speed is partly practical. Dominic McLaughlin, Arabella Stanton and Alastair Stout are playing children whose ages matter to the story, and HBO has previously acknowledged that the production cannot afford enormous gaps between installments.

Season 2 is expected to move into filming in fall 2026.

The new trio of cast additions joins Kit Harington as Gilderoy Lockhart, who came aboard after Nicholas Hoult left the part because of scheduling conflicts.

Year 2 has a different casting challenge

Philosopher's Stone had to establish almost everybody at once: Harry, Ron, Hermione, the Hogwarts faculty and the Weasley family.

Chamber of Secrets has fewer introductions, but several of them carry much more narrative weight. Dobby repeatedly changes Harry's path. Tom Riddle holds the answer to the mystery. Ginny sits much closer to its center than she initially appears.

All three are now cast months before viewers have seen HBO's first full season.