Broadbent is the first new face for the series' next instalment, reported Aceshowbiz.
His role is kept under wraps, but it is said to be a "significant" one.
Broadbent won an Oscar for his role in 2001's film "Iris". The 67-year-old British actor is also known for his role in "Moulin Rouge!".
His other credits include films "Time Bandits", "Brazil", "Bridget Jones's Diary" and the "Harry Potter" film franchise (as Horace Slughorn) as well as TV movie "Longford" that helped him earn a Golden Globe Award and an Emmy nomination.