The British actor takes over the role that Kenneth Branagh previously played in the "Harry Potter" films. In JK Rowling's books, Gilderoy Lockhart is a famous writer who becomes the Defense Against the Dark Arts teacher during Harry Potter's second year at Hogwarts School of Witchcraft and Wizardry.
Nicholas Hoult has previously starred in films such as "X-Men", "Superman" and "Mad Max: Fury Road".
The first season of the series is expected to premiere this Christmas. Hoult will appear in the second season, writes the BBC.
The lead role of Harry Potter is played by Scot Dominic McLaughlin. Potter's friends Hermione Granger and Ron Weasley are played by Arabella Stanton and Alastair Stout, respectively.
