X-Men: Days of Future Past alum Nicholas Hoult has joined season two of HBO's Harry Potter TV show (based on Chamber of Secrets) as Defense Against the Dark Arts teacher Gilderoy Lockhart. Season two of HBO's Harry Potter TV show, which will tackle Chamber of Secrets, has found its Gilderoy Lockhart in X-Men: Days of Future Past alum Nicholas Hoult. Nicholas Hoult Joins Harry Potter TV Show as Gilderoy Lockhart in Season 2