New Delhi, Sept. 4 -- HBO has expanded the cast of its upcoming Harry Potter series, with Billy Barratt, Lenny Rush, and Bonnie Hill joining Season 2 as Tom Riddle, Dobby, and Ginny Weasley, respectively. The first season is also set to introduce a new generation of Hogwarts students to audiences this Christmas.

The three actors will appear in the second season, which is set to adapt Harry Potter and the Chamber of Secrets - the second book in JK Rowling's seven-part series. Production is already moving ahead at Leavesden Studios in the UK, with HBO having renewed the series before its first episode even premiered.

Rush will play Dobby the house-elf who attempts to prevent Harry from returning to Hogwarts. This ends up forming one of th...